CN119511461A

CN119511461A - A wavelength selective switch and node device

Info

Publication number: CN119511461A
Application number: CN202311065248.1A
Authority: CN
Inventors: 李腾浩; 王庆丰; 姚文杰; 李世强
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2023-08-22
Filing date: 2023-08-22
Publication date: 2025-02-25

Abstract

The embodiments of the present application provide a wavelength selection switch and a node device, which relate to the field of optical communications and are used to improve the problem that crosstalk and insertion loss between ports affect the expansion of the number of ports. The wavelength selection switch includes an optical fiber array, and the optical fiber array includes a first port and multiple second ports; the first port is arranged on a first reference line; the multiple second ports are divided into a first part and a second part located on both sides of the first reference line, and at least one of the first port, the first part and the second part is located on one side of the second reference line; when the first port is arranged at the center of the optical path, the first part and the second part are arranged asymmetrically relative to the first port. The distance of the first port relative to the second reference line and the maximum distance of the second port in the first part and the second part relative to the second reference line are both less than or equal to 2 times the port size. The above-mentioned wavelength selection switch can be used as a node device in an optical network.

Description

Wavelength selective switch and node device

Technical Field

The present application relates to the field of optical communications technologies, and in particular, to a wavelength selective switch and a node device.

Background

Optical networks are evolving continuously towards high capacity, low latency, and intelligent. Optical switching technologies such as reconfigurable optical add-Drop multiplexers (Reconfigurable Optical Add-Drop multiplexers, abbreviated ROADM) and optical cross-Connect (OXC) are one of the key technologies for implementing optical networks with the above characteristics.

Wavelength selective switches (WAVELENGTH SELECTIVE SWITCH, WSS) are used as core devices for ROADMs and OXCs, and place higher demands on the number of ports of the wavelength selective switch against the development of optical networks. However, the cross-talk between ports and the port insertion loss in the wavelength selective switch affect the expansion of the number of ports. Therefore, how to improve the influence of the inter-port crosstalk and the port insertion loss on the expansion of the number of ports is a problem to be solved.

Disclosure of Invention

The embodiment of the application provides a wavelength selective switch and a node device, which are used for solving the problem that port crosstalk and port insertion loss affect port number expansion.

In order to achieve the above purpose, the embodiment of the present application adopts the following technical scheme:

In a first aspect, embodiments of the present application provide a wavelength selective switch comprising an array of optical fibers and a spatial light modulator. The fiber array includes a first port and a plurality of second ports.

The plurality of second ports are divided into a first part and a second part which are positioned at two sides of the first reference line, at least one of the first ports, the first part and the second part is positioned at one side of the second reference line, and the first parts and the second parts are asymmetrically arranged relative to the first ports under the condition that the first ports are arranged at the center of the optical path.

In the optical fiber array, the distance between the first port and the second reference line is a first distance, the maximum distance between the second port and the second reference line in the first part is a second distance, the maximum distance between the second port and the second reference line in the second part is a third distance, and the first distance, the second distance and the third distance are all smaller than or equal to 2 times of the port size.

The optical path center is a position where an input light spot and an output light spot in the optical fiber array coincide when the spatial light modulator is used as a reflecting mirror surface, the first reference line is parallel to the dispersion direction, the second reference line is parallel to the port direction, the intersection point of the first reference line and the second reference line is the optical path center, and the port size is the size of the first port in the dispersion direction.

In the wavelength selective switch provided by the embodiment of the application, the plurality of second ports of the optical fiber array comprise a first part and a second part which are respectively arranged at two sides of the first reference line, and the first part, the second part and the first ports adopt an offset and asymmetric arrangement mode.

By adopting the design that the second ports are arranged on the two sides of the first reference line, the ports are switched by using the bilateral deflection of the spatial light modulator, so that more optical fiber ports can be supported under the condition that the diffraction deflection angle ranges supported by the spatial light modulator are the same, and the application scenes of large ports, such as 64D, 128D and the like, can be met. Or under the condition that the number of the optical fiber ports is the same, the port insertion loss is reduced.

On the other hand, the optical fiber array adopts an offset and asymmetric arrangement mode, which is beneficial to improving the condition that diffracted light beams with crosstalk orders enter the optical fiber ports in the wavelength selective switch for carrying out port switching by adopting bilateral deflection in the spatial light modulator, thereby improving the problem of crosstalk between the optical fiber ports and being beneficial to improving the isolation degree and the directivity of the wavelength selective switch.

Moreover, the diffraction deflection angle of the spatial light modulator in the dispersion direction can be limited by limiting the first distance, the second distance and the third distance to be less than or equal to 2 times of port sizes, so that the requirement on the diffraction deflection angle range of the spatial light modulator in the dispersion direction can be reduced while the compactness of port arrangement in the optical fiber array is ensured, the port insertion loss is reduced, and the performance of the wavelength selective switch is improved.

The first port may be located at one side of the first reference line or may be located on the first reference line, and further, the first port may be further located at a center position of the optical path.

In some embodiments, the first portion and the second portion each comprise at least two second ports, wherein the second ports in the first portion are arranged along a line parallel to the second reference line and the second ports in the second portion are arranged along a line parallel to the second reference line.

In the wavelength selective switch provided by the embodiment of the application, the second ports in the first part and the second part are all in linear arrangement, and the arrangement straight line is parallel to the second reference line. On the one hand, the optical fiber ports which are arranged in a linear mode are easier to manufacture and ensure position accuracy, so that manufacturing difficulty of the optical fiber array can be reduced, on the other hand, the optical fiber ports which are arranged in parallel with the second reference line are more beneficial to port switching, complexity of a port switching process can be reduced, the port switching can be realized more rapidly and accurately, and the performance of the wavelength selective switch can be improved.

In some embodiments, the first port, the first portion, and the second portion are located on the same side of the second reference line, and the orthographic projection positions on the first reference line are the same. By the design, bilateral deflection is realized, crosstalk orders are prevented from entering the optical fiber port, port insertion loss is reduced, complexity of a port switching process can be reduced, port switching can be realized more rapidly and accurately, and performance of the wavelength selective switch is improved.

In some embodiments, the first port, the second port in the first portion, and the second port in the second portion are equidistant from the second reference line by an amount equal to 0.5 times the size of the ports. By the design, the port arrangement compactness in the optical fiber array can be ensured, meanwhile, the requirement on the diffraction deflection angle range of the space optical modulator in the dispersion direction is reduced, and the port insertion loss is reduced and the performance of the wavelength selective switch is improved.

In some embodiments, the orthographic position of the first portion and the second portion on the first reference line is the same, and the orthographic position of the first port and the first portion on the first reference line is different. By the design, in some scenes, the port switching can be performed by adopting the one-dimensional diffraction grating while the double-side deflection and the crosstalk problem improvement are realized, so that the reduction of the port insertion loss is facilitated.

In some embodiments, the spacing of the orthographic projection positions of the first port and the first portion on the first reference line is greater than or equal toMultiple port sizes. By the design, the compactness of port arrangement in the optical fiber array can be improved, and meanwhile, the problem that the processing difficulty is increased, the control accuracy is reduced, the requirement on control accuracy is high, crosstalk is increased and the like due to the fact that the distance between ports is too close is solved.

In some embodiments, the first port is located on the second reference line;

or the first portion and the second portion are both located on a second reference line;

Or the first port and the first portion are located on either side of the second reference line, respectively.

The wavelength selective switch provided by the embodiment of the application has the advantages that the optical fiber array can adopt a plurality of different arrangement modes, the design is flexible, the adaptability is strong, and the wavelength selective switch can be suitable for a plurality of different application scenes.

In some embodiments, the first port and the first portion are located on opposite sides of the second reference line, respectively, and the first port and the second port in the first portion are equidistant from the second reference line. In the wavelength selective switch provided by the embodiment of the application, the first port and the aligned first part and second part in the optical fiber array are symmetrically arranged relative to the second reference line, so that the complexity of the port switching process can be reduced, the port switching can be realized more rapidly and accurately, and the performance of the wavelength selective switch is improved. In addition, the method can be realized through a one-dimensional diffraction grating in both an up-wave scene and a down-wave scene, and is beneficial to reducing port insertion loss.

In some embodiments, the first port and the second port in the first portion are each a port size from a second reference lineOr 0.5 times. By the design, deflection angles in the dispersion direction in the port switching process are reduced conveniently, so that the port arrangement compactness in the optical fiber array can be ensured, the requirement on the diffraction deflection angle range of the space optical modulator in the dispersion direction is reduced, the port insertion loss is reduced, and the performance of the wavelength selective switch is improved.

In some embodiments, the orthographic projection positions of the first portion and the second portion on the first reference line are different, and the first port is different from the first portion or the second portion. By the design, the port switching can be performed by adopting the one-dimensional diffraction grating in some scenes while the double-side deflection and the crosstalk problem are realized, and the reduction of the port insertion loss is facilitated.

In some embodiments, the first portion is located on the second reference line, or the second portion is located on the second reference line, or the first portion and the second portion are located on either side of the second reference line, respectively.

In some embodiments, the spacing of the orthographic positions of the first and second portions on the first reference line is equal to the port size. By the design, deflection angles in the dispersion direction in the port switching process are reduced conveniently, so that the port arrangement compactness in the optical fiber array can be ensured, the requirement on the diffraction deflection angle range of the space optical modulator in the dispersion direction is reduced, the port insertion loss is reduced, and the performance of the wavelength selective switch is improved.

In some embodiments, the orthographic projection positions of the first port, the first portion, and the second portion on the first reference line are all different. By the design, the possibility that the diffracted light beams of crosstalk orders enter the optical fiber port can be further avoided, and the isolation degree and the directivity of the wavelength selective switch can be improved.

In some embodiments, the first port is located at the center of the optical path, the first portion and the second portion are located on the same side of the second reference line, or the first portion and the second portion are located on opposite sides of the second reference line, respectively. The wavelength selective switch provided by the embodiment of the application has the advantages that the optical fiber array can adopt a plurality of different arrangement modes, the design is flexible, the adaptability is strong, and the wavelength selective switch can be suitable for different application scenes.

In some embodiments, the number of second ports in the first portion and the second portion are equal, the second ports in the first portion and the second ports in the second portion are arranged at the same pitch in the port direction, and the minimum distance between the second ports in the first portion and the first reference line is equal to the minimum distance between the second ports in the second portion and the first reference line. By the design, diffraction deflection angles of two sides of the spatial light modulator during bilateral deflection can be fully utilized, so that port insertion loss is reduced.

In some embodiments, the wavelength selective switch further comprises an intermediate optical assembly positioned between the fiber array and the spatial light modulator, the intermediate optical assembly for optically modulating a light beam transmitted between the fiber array and the spatial light modulator. The optical component is used for carrying out optical adjustment on the light beams transmitted between the optical fiber array and the spatial light modulator, thereby being beneficial to the accurate and efficient transmission of the light beams between the spatial light modulator and the optical fiber array on one hand, and being beneficial to the adjustment of the optical path layout of the wavelength selective switch on the other hand, so as to be beneficial to the reduction of the size of the wavelength selective switch.

In some embodiments, the spatial light modulator is a liquid crystal on silicon. The liquid crystal on silicon has the characteristic of flexible Grid (Flex-Grid) and supports flexible allocation of the bandwidth of the wavelength selective switch channel.

In a second aspect, an embodiment of the present application provides a node arrangement comprising at least one wavelength selective switch according to any of the embodiments of the first aspect.

The technical effects that the node device provided by the embodiment of the present application can achieve are the same as those that the wavelength selective switch in any one of the above embodiments, and are not described herein.

Drawings

Fig. 1 is a schematic structural diagram of an optical network according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of a wavelength selective switch according to an embodiment of the present application;

FIG. 3 is a front view of a LCOS according to an embodiment of the present application;

FIG. 4 is a cross-sectional view of the LCOS of FIG. 3;

FIG. 5 is a schematic diagram of the liquid crystal on silicon of FIG. 3 in forming a one-dimensional diffraction grating;

FIG. 6 is a schematic diagram of the LCOS of FIG. 3 in forming a two-dimensional diffraction grating;

FIG. 7 is a schematic diagram of a dispersive light spot and a pixel area according to an embodiment of the present application;

FIG. 8 is a schematic diagram illustrating the arrangement of an optical fiber array in a wavelength selective switch according to the related art;

FIG. 9 is a schematic diagram of the operation of the fiber array of FIG. 8;

fig. 10 is a schematic diagram of an optical fiber array arrangement in a wavelength selective switch according to an embodiment of the present application;

FIG. 11A is a schematic diagram of a port plane optical path of a wavelength selective switch in a downlink scenario according to an embodiment of the present application;

FIG. 11B is a schematic diagram of a dispersion plane optical path of a wavelength selective switch in a down-wave scenario according to an embodiment of the present application;

FIG. 12 is a diagram showing a positional relationship between a diffracted beam and an optical fiber array in a downlink scenario for a wavelength selective switch according to an embodiment of the present application;

Fig. 13A is a schematic diagram of a port plane optical path of a wavelength selective switch in an uplink scene according to an embodiment of the present application;

FIG. 13B is a schematic diagram of a dispersive planar optical path of a wavelength selective switch in an uplink scenario according to an embodiment of the present application;

FIG. 14 is a diagram showing the positional relationship between a diffracted beam and an optical fiber array in an uplink scene of a wavelength selective switch according to an embodiment of the present application;

Fig. 15 is a schematic diagram of an optical fiber array arrangement in another wavelength selective switch according to an embodiment of the present application;

fig. 16A is a schematic diagram of a port plane optical path of a wavelength selective switch in a downlink scenario according to an embodiment of the present application;

FIG. 16B is a schematic diagram of a dispersion plane optical path of a wavelength selective switch in a down-wave scenario according to an embodiment of the present application;

FIG. 17 is a diagram showing the positional relationship between a diffracted beam and an optical fiber array in a down-wave scenario for a wavelength selective switch according to an embodiment of the present application;

FIG. 18A is a schematic diagram of a port plane optical path of a wavelength selective switch in a winding scene according to an embodiment of the present application;

FIG. 18B is a schematic diagram of a dispersive planar optical path of a wavelength selective switch in a winding scenario according to an embodiment of the present application;

FIG. 19 is a diagram showing the positional relationship between a diffracted beam and an optical fiber array in a winding scene of a wavelength selective switch according to an embodiment of the present application;

FIG. 20 is a schematic diagram illustrating an arrangement of an optical fiber array in another wavelength selective switch according to an embodiment of the present application;

FIG. 21A is a schematic diagram of a port plane optical path of a wavelength selective switch in a downlink scenario according to an embodiment of the present application;

FIG. 21B is a schematic diagram of a dispersion plane optical path of a wavelength selective switch in a down-wave scenario according to an embodiment of the present application;

FIG. 22 is a diagram showing the positional relationship between a diffracted beam and an optical fiber array in a down-wave scenario for a wavelength selective switch according to an embodiment of the present application;

FIG. 23A is a schematic diagram of a port plane optical path of a wavelength selective switch in a winding scene according to an embodiment of the present application;

FIG. 23B is a schematic diagram of a dispersive planar optical path of a wavelength selective switch in an uplink scenario according to an embodiment of the present application;

FIG. 24 is a diagram showing the positional relationship between a diffracted beam and an optical fiber array in an uplink scene for a wavelength selective switch according to an embodiment of the present application;

FIG. 25 is a schematic diagram illustrating an arrangement of an optical fiber array in another wavelength selective switch according to an embodiment of the present application;

fig. 26A is a schematic diagram of a port plane optical path of a wavelength selective switch in a downlink scenario according to an embodiment of the present application;

FIG. 26B is a schematic diagram of a dispersion plane optical path of a wavelength selective switch in a down-wave scenario according to an embodiment of the present application;

FIG. 27 is a diagram showing the positional relationship between a diffracted beam and an optical fiber array in a down-wave scenario for a wavelength selective switch according to an embodiment of the present application;

fig. 28A is a schematic diagram of a port plane optical path of a wavelength selective switch in a winding scene according to an embodiment of the present application;

FIG. 28B is a schematic diagram of a dispersive planar optical path of a wavelength selective switch in a winding scenario according to an embodiment of the present application;

Fig. 29 is a diagram showing a positional relationship between a diffracted beam and an optical fiber array in a winding scene of a wavelength selective switch according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application. It will be apparent that the described embodiments are only some, but not all, embodiments of the application.

In the following, in the embodiments of the present application, the terms "first", "second", etc. are used for descriptive convenience only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the embodiments of the present application, "upper", "lower", "left" and "right" are not limited to the orientation in which the components in the drawings are schematically disposed, but it should be understood that these directional terms may be relative concepts, which are used for descriptive and clarity with respect thereto, which may be varied accordingly with respect to the orientation in which the components in the drawings are disposed.

In embodiments of the present application, the term "comprising" is to be construed as an open, inclusive meaning, i.e. "including, but not limited to", throughout the specification and claims, unless the context requires otherwise. In the description of the present specification, the terms "one embodiment," "some embodiments," "example embodiments," "exemplary," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with the embodiment or example is included in at least one embodiment or example of the application. The schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

As used herein, "about," "approximately" or "approximately" includes the stated values as well as average values within an acceptable deviation range of the particular values as determined by one of ordinary skill in the art in view of the measurement in question and the errors associated with the measurement of the particular quantity (i.e., limitations of the measurement system).

As used herein, "parallel", "perpendicular", "equal" includes the stated case as well as the case that approximates the stated case, the range of which is within an acceptable deviation range as determined by one of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the particular quantity (i.e., limitations of the measurement system). For example, "parallel" includes absolute parallel and approximately parallel, where the range of acceptable deviation of approximately parallel may be, for example, within 5 ° of deviation, and "perpendicular" includes absolute perpendicular and approximately perpendicular, where the range of acceptable deviation of approximately perpendicular may also be, for example, within 5 ° of deviation. "equal" includes absolute equal and approximately equal, where the difference between the two, which may be equal, for example, is less than or equal to 5% of either of them within an acceptable deviation of approximately equal.

It will be understood that when a layer or element is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present between the layer or element and the other layer or substrate.

Exemplary embodiments are described in the examples of the application with reference to cross-sectional and/or plan views and/or equivalent circuit diagrams as idealized exemplary figures. In the drawings, the thickness of layers and regions are exaggerated for clarity. Thus, variations from the shape of the drawings due to, for example, manufacturing techniques and/or tolerances, are to be expected. Thus, the exemplary embodiments should not be construed as limited to the shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of example embodiments.

The embodiment of the application provides a node device which can be applied to an optical network as shown in fig. 1. The optical network 1000 may be used in a variety of communication scenarios. Such as local trunks, long-haul trunks, global communications networks, public telecommunications networks of various countries. The optical network may also be used for transmission of television signals, industrial production site monitoring and scheduling, traffic monitoring control command, town cable television network, public antenna system (community antenna television, abbreviated CATV), and fiber optic local area network, etc.

The optical network 1000 may include a plurality of node devices connected to each other through optical channels. One of the node devices may be connected to any number of other node devices 100. The node apparatus 100 may be a reconfigurable optical add-drop multiplexer (abbreviated ROADM) or an optical cross-connect (abbreviated OXC). In some embodiments of the present application, the node apparatus 100 may include a plurality of optical wavelength selection switches (WAVELENGTH SELECTIVE SWITCH, abbreviated WSS) for implementing wavelength scheduling functions between different dimensions.

The embodiment of the present application also provides a wavelength selective switch, which can be applied to the node device 100 in the above embodiment, and as shown in fig. 2, the wavelength selective switch 1 includes a liquid crystal on silicon 4, an optical fiber array 2, and an intermediate optical component 3 disposed between the liquid crystal on silicon 4 and the optical fiber array 2.

The lc-on-silicon 4 is a reflective diffraction grating that is programmable to achieve a specific phase distribution, and has the main function of deflecting the incident beam to a corresponding exit direction. Fig. 3 is a front view of a liquid crystal on silicon 4 according to an embodiment of the present application, as shown in fig. 3, the liquid crystal on silicon 4 includes a Pixel array, and the Pixel array includes a plurality of pixels (pixels) 41 arranged in a plurality of rows and columns along a first direction and a second direction, and the first direction and the second direction are perpendicular to each other. Taking the orientation shown in fig. 3 as an example, the first direction is a lateral direction, the second direction is a longitudinal direction, the row direction in the pixel array may be parallel to the first direction, and the column direction may be parallel to the second direction.

Fig. 4 is a cross-sectional view of the liquid crystal on silicon 4 of fig. 3, and as shown in fig. 4, the liquid crystal on silicon 4 includes a silicon substrate 403, a transparent cover plate 401, and a liquid crystal layer 402, the silicon substrate 403 and the transparent cover plate 401 being disposed opposite to each other, and the liquid crystal layer 402 being disposed between the oppositely disposed silicon substrate 403 and transparent cover plate 401. The silicon substrate 403 has a reflective layer capable of reflecting an incident light beam, and is further provided with an array arrangement of pixel circuits, wherein the pixel circuits include a first electrode 405 corresponding to the pixels 41, and a second electrode 404 is disposed on one side of the transparent cover plate 401 adjacent to the silicon substrate 403.

In this case, by applying a voltage to the second electrode 404 and adjusting the voltage applied to the different first electrodes 405 in the pixel circuit, the deflection angle of the liquid crystal molecules in the portion of the liquid crystal layer 402 corresponding to the position of the first electrode 405, that is, the deflection angle of the liquid crystal molecules in the pixel can be controlled. Due to the birefringence effect of the liquid crystal molecules, different voltages applied between the first electrode 405 and the second electrode 404 will correspond to different amounts of phase retardation, so that a structure similar to a blazed grating (Blazed grating) can be formed. Since the diffraction deflection angle of the blazed grating depends on the grating period of the blazed grating, the diffraction deflection angle of the incident beam can be controlled by changing the grating period corresponding to different positions on the liquid crystal on silicon 4, and the diffraction and deflection of the incident beam can be realized.

In addition, since the port insertion loss in the wavelength selective switch 1 is positively correlated with the diffraction deflection angle of the liquid crystal on silicon 4, i.e., the larger the diffraction deflection angle is, the larger the port insertion loss is. Thus once the port insertion loss baseline is determined, the range of diffraction deflection angles that can be supported by the lc-on-silicon 4 is also determined.

The liquid crystal on silicon 4 may be a one-dimensional diffraction grating in which blazed gratings are formed only in the second direction, as shown in fig. 5, the grating direction of the blazed grating 5 formed in the second direction is parallel to the second direction, the blazed grating 5 is capable of diffracting and deflecting the incident light beam in the second direction, and the one-dimensional diffraction grating is capable of reflecting only the incident light beam in the first direction and corresponds to the function of a reflecting mirror.

The liquid crystal on silicon 4 may be a two-dimensional diffraction grating in which blazed gratings 5 are formed in both the first direction and the second direction, and as shown in fig. 6, the liquid crystal on silicon 4 may form a first blazed grating and a second blazed grating in the first direction and the second direction, respectively, the grating direction of the first blazed grating being parallel to the first direction and being capable of diffracting and deflecting an incident light beam in the first direction, and the grating direction of the second blazed grating being parallel to the second direction and being capable of diffracting and deflecting an incident light beam in the second direction. Diffraction and deflection of an incident light beam in any direction can be achieved through the combined action of the first blazed grating and the second blazed grating.

In the embodiment of the present application, the liquid crystal on silicon 4 adopts a one-dimensional diffraction grating or a two-dimensional diffraction grating, which can be determined according to the arrangement condition of the optical fiber array 2, the application scenario, and the like, and the description can be referred to below specifically.

With continued reference to fig. 2, the wavelength selective switch 1 further includes an optical fiber array 2, where the optical fiber array 2 includes a plurality of optical fiber ports, and the plurality of optical fiber ports includes a first port D ₀ and a plurality of second ports (D ₁ to D _N), where the first port D ₀ is a COM port, i.e., a common port, and the second port is a (D ₁ to D _N) non-COM port. That is, the wavelength selective switch 1 provided in the embodiment of the present application adopts a1×n architecture.

The first port and the second port in the optical fiber array 2 have different roles in different working scenarios of the wavelength selective switch 1, and the working scenarios of the wavelength selective switch 1 can be divided into an up-wave scenario and a down-wave scenario. In the down-wave scenario, as shown by the solid arrow in fig. 2, the first port D ₀ is used for receiving the incident light beam, the wavelength selective switch 1 processes the incident light beam to form an outgoing light beam, and the outgoing light beam is output through the second ports (D ₁ to D _N), that is, the target port for outputting the outgoing light beam in the down-wave scenario is one second port (D ₁ to D _N). In the upwave scenario, as indicated by the dashed arrows in fig. 2, the second ports (D ₁ to D _N) are used for receiving the incident light beam, the wavelength selective switch 1 processes the incident light beam to form an outgoing light beam, and the outgoing light beam is output through the first port D ₀, that is, the target port for outputting the outgoing light beam in the upwave scenario is the first port D ₀.

The incident light beams received by the first port D ₀ in the downlink scene and the incident light beams received by the second ports (D ₁ to D _N) in the uplink scene can be mixed together for optical signals with different wavelengths to form a multi-wavelength mixed signal, and the multi-wavelength mixed signal is transmitted in the same optical fiber port, so that the wavelength division multiplexing (WAVELENGTH DIVISION MULTIPLEXING, WDM) technology can be realized, and the aim of high-speed data transmission can be achieved.

In the case where the incident light beam is a multi-wavelength mixed signal, the multi-wavelength mixed signal is irradiated onto the liquid crystal on silicon 4 through the intermediate optical assembly 3. As shown in fig. 7, the intermediate optical component 3 may spatially separate the optical signals of each wavelength in the multi-wavelength mixed signal, and respectively project the optical signals of different wavelengths to different positions of the liquid crystal on silicon 4, so as to form a plurality of dispersive light spots (λ1 to λ _M) arranged along the same straight line on the liquid crystal on silicon 4. The direction in which the alignment lines of the plurality of dispersed spots (λ1 to λ _M) are located may be parallel to the first direction or the second direction. The direction in which the straight lines of the dispersed spots (λ1 to λ _M) are arranged is exemplified herein as being parallel to the first direction, and a person skilled in the art can adapt the scheme to be parallel to the second direction according to the description herein.

With continued reference to fig. 7, the pixel array of the liquid crystal on silicon 4 is divided into a plurality of pixel areas 42 according to the dispersion light spots, the plurality of pixel areas 42 have a corresponding relationship with the dispersion light spots of different wavelengths, and one pixel area 42 corresponds to one dispersion light spot (one of λ1 to λ _M) of a specific wavelength. The liquid crystal on silicon 4 can form a blazed grating acting on a dispersion light spot (one of λ1 to λ _M) projected to the pixel region 42 by controlling pixels in the pixel region 42, and an outgoing light beam which can be outgoing through a target port is formed through the intermediate optical component 3 after the dispersion light spot (one of λ1 to λ _M) is diffracted and deflected by the blazed grating.

Also, with the wavelength selective switch 1 employing the 1×n architecture, since the dispersion light spot projected onto the liquid crystal on silicon 4 is only one line extending in the first direction, the plurality of pixel areas 42 on the liquid crystal on silicon 4 are also only one line arranged in the first direction. In this case, the length of the pixel region 42 in the first direction (dispersion direction) is much smaller than the length in the second direction, that is, the pixel region 42 is in the shape of a "stripe". As is clear from the above, the diffraction deflection angle of the liquid crystal on silicon 4 to the incident light beam is related to the grating period, and the adjustment of the grating period is related to the length of the pixel region 42 in the grating direction, so that in the case where the length of the pixel region 42 in the first direction is much smaller than the length in the second direction, the diffraction deflection angle range that the pixel region 42 can support for the dispersed light spot in the first direction is much smaller than the diffraction deflection angle range that can support in the second direction.

Since the working principle of the liquid crystal on silicon 4 is based on the diffraction effect, when the liquid crystal on silicon 4 is used as an optical engine to load a blazed grating, a plurality of diffraction orders of diffraction beams, such as-2-order, -1-order, 0-order, +1-order, +2-order and the like, are generated. The diffracted light beams of the respective diffraction orders are arranged on a straight line parallel to the grating direction of the blazed grating, and the diffracted light beams of the positive and negative orders are symmetrically distributed with respect to the diffracted light beam of the 0 th order.

In the wavelength selective switch 1, the +1 order is selected as the target order, and diffraction orders other than the +1 order are crosstalk orders. In the working process of the wavelength selective switch 1, the blazed grating formed by the liquid crystal on silicon 4 is controlled to deflect the +1 diffraction beam to the target port to be emitted, in this case, other diffraction orders, namely diffraction beams of crosstalk orders, possibly enter other optical fiber ports, and when diffraction beams of crosstalk orders enter other optical fiber ports, crosstalk problems among the optical fiber ports can be caused, so that the isolation degree and the directivity of the wavelength selective switch 1 are affected.

In order to improve the crosstalk problem caused by the diffracted light beams of the crosstalk order entering other optical fiber ports, a wavelength selective switch 1 is provided in the related art, and as shown in fig. 8, the optical fiber array 2 in the wavelength selective switch 1 includes a plurality of optical fiber ports arranged along a straight line, the plurality of optical fiber ports are a first port D ₀ and a plurality of second ports (D ₁ to D _N), respectively, and the plurality of second ports (D ₁ to D _N) are all arranged on one side of the first port D ₀. Referring to fig. 9, when the first port D ₀ receives the incident light beam and outputs the incident light beam in a second port (e.g., D ₂), the optical fiber ports can be prevented from being performed by all the diffracted light beams of the negative orders, so as to improve the crosstalk problem between the optical fiber ports.

However, in the wavelength selective switch 1 provided in the related art, in order to improve the crosstalk problem between the optical fiber ports, the liquid crystal on silicon 4 is single-side deflected, and only the diffraction deflection angle at one side of the liquid crystal on silicon 4 is half of the diffraction deflection angle range that can be supported by the liquid crystal on silicon 4, so that the expansion of the number of the optical fiber ports in the optical fiber array 2 is not facilitated, and the requirement of a large-port application scene on the number of ports is difficult to meet.

Based on this, the embodiment of the present application provides a wavelength selective switch 1, and the arrangement manner of the optical fiber array 2 in the wavelength selective switch 1 is improved, so as to improve the problem that the port crosstalk problem affects the port number expansion.

For convenience of description of the optical fiber array 2, an optical path center, a dispersion direction, a first reference line, a port direction, and a second reference line are defined herein, respectively. Referring to fig. 10, the optical path center O is a position where an input light spot of an incident light beam and an output light spot of a reflected light beam reflected by the liquid crystal on silicon 4 overlap in the optical fiber array 2 when the liquid crystal on silicon 4 does not generate a phase diagram, i.e., corresponds to a mirror surface.

Dispersion direction X when the liquid crystal on silicon 4 forms a blazed grating in the first direction, the directions parallel to the straight line where the spot centers of the diffracted light fluxes of the respective diffraction orders are located are the dispersion direction X. When the liquid crystal on silicon 4 generates blazed gratings of different grating periods in the first direction, the locus of the center of the spot of the +1st-order diffracted beam is also parallel to the dispersion direction X, that is, the dispersion direction X is the direction corresponding to the first direction in the liquid crystal on silicon 4, that is, the direction corresponding to the direction in which the dispersed spots of different wavelengths are arranged.

The first reference line L ₁ is a straight line passing through the optical path center O and parallel to the dispersion direction X, and the first port D ₀ is positioned at the optical path center O and receives the incident light beam from another angle, and when the LCOS 4 generates blazed gratings with different grating periods in the first direction, the spot center track of the +1-order diffraction light beam is the first reference line L ₁.

Port direction Y when the liquid crystal on silicon 4 forms a blazed grating in the second direction, the spot centers of the diffracted light beams of the respective diffraction orders are collinear, and the direction parallel to the straight line where the spot center of the diffracted light beam of the respective diffraction orders is located is the port direction Y. When the liquid crystal on silicon 4 generates blazed gratings with different grating periods in the second direction, the central track of the spot of the +1 order diffraction beam is parallel to the port direction Y, that is, the port direction Y is the direction corresponding to the second direction in the liquid crystal on silicon 4, and the port direction Y is perpendicular to the dispersion direction X.

The second reference line L ₂ is a straight line passing through the optical path center O and parallel to the port direction Y, the first port D ₀ is positioned at the optical path center O and receives the incident light beam from another angle, when the liquid crystal on silicon 4 generates blazed gratings with different grating periods in the second direction, the light spot center track of the +1 diffraction light beam is output, namely the second reference line L ₂, and the first reference line L ₁ and the second reference line L ₂ are mutually perpendicular.

In the wavelength selective switch 1 provided by the embodiment of the application, the optical fiber array 2 comprises a plurality of optical fiber ports, the plurality of optical fiber ports comprise a first port D ₀ and a plurality of second ports (D ₁ to D _N), wherein the first port D ₀ is positioned on a first reference line L ₁, the plurality of second ports (D ₁ to D _N) comprise a first part 21 and a second part 22 which are respectively positioned on two sides of the first reference line L ₁, the second ports in the first part 21 are arranged along a direction parallel to a second reference line L2, and the second ports in the second part 22 are arranged along a direction parallel to the second reference line L2.

Herein, the distances defining the first port D ₀, the first portion 21, and the second portion 22 with respect to the second reference line L ₂ are a first distance, a second distance, and a third distance, respectively. In the optical fiber array 2 adopting the above design, at least one of the first distance, the second distance and the third distance is not equal to 0, and in the case that the first distance is equal to 0 and both the second distance and the second distance are greater than 0, the first portion 21 and the second portion 22 are asymmetrically arranged with respect to the first port D ₀.

That is, at least one of the first port D ₀, the first portion 21, and the second portion 22 is located on one side of the second reference line L ₂, and the first portion 21 and the second portion 22 are asymmetrically disposed with respect to the first port D ₀ in a case where the first port D ₀ is located on the second reference line L ₂ and the first portion 21 and the second portion 22 are located on both sides of the second reference line L ₂, respectively.

It should be noted that, herein, the first portion 21 and the second portion 22 are disposed asymmetrically with respect to the first port D ₀, which means that the first portion 21 and the second portion 22 are disposed non-point symmetrically with respect to the first port D ₀. While the "point symmetrical" arrangement of the first and second portions 21, 22 with respect to the first port D ₀ means that the new position happens to coincide with the home position after the first and second portions 21, 22 are rotated 180 degrees about the first port D ₀. The arrangement of non-point symmetry refers to the arrangement other than point symmetry.

In addition, in the optical fiber array 2 provided in the embodiment of the present application, the first distance, the second distance, and the third distance are all less than or equal to 2 times of the port size, where the port size is the size of the optical fiber port, and the size of the size is related to the adapted optical fiber specification. Illustratively, the size of the port dimensions may range from 60 μm to 300 μm. Since the first port D ₀ and the second ports (D ₁ to D _N) are circular ports of the same size, the port size may be the size of the first port D ₀ in the dispersion direction X or the port direction Y, or the size of the second port (D ₁ to D _N) in the dispersion direction X or the port direction Y.

It should be noted that, the distances related to the optical fiber ports (the first port D ₀ and the second ports (D ₁ to D _N)) are all measured with respect to the center of the optical fiber port. For example, the distance of the first port D ₀ with respect to the second reference line L ₂ refers to the distance of the port center of the first port D ₀ with respect to the second reference line L ₂, and the distance of the first portion 21 with respect to the second reference line L ₂ refers to the distance of the port center of the second port in the first portion 21 with respect to the second reference line L ₂.

As can be seen from the above description, in the optical fiber array 2 provided in the embodiment of the present application, the plurality of second ports (D ₁ to D _N) includes the first portion 21 and the second portion 22 that are disposed on both sides of the first reference line L ₁, at least one of the first portion 21, the second portion 22 and the first port D ₀ is located on one side of the second reference line L ₂, and the three are arranged asymmetrically with respect to the optical path center O, that is, in an offset, asymmetric arrangement.

By adopting the design that the second ports are arranged on two sides of the first reference line L ₁, the ports are switched by utilizing the bilateral deflection of the LCOS 4, so that more optical fiber ports can be supported under the condition that the diffraction deflection angle ranges supported by the LCOS 4 are the same, and the application scenes of large ports, such as 64D, 128D and the like, can be met. Or under the condition that the number of the optical fiber ports is the same, the port insertion loss is reduced.

On the other hand, the optical fiber array 2 adopts an offset and asymmetric arrangement mode, which is beneficial to improving the condition that diffracted light beams with crosstalk orders enter the optical fiber ports, so that the problem of crosstalk between the optical fiber ports can be improved, and the isolation degree and the directivity of the wavelength selective switch 1 are improved.

In yet another aspect, the distribution ranges of the first port D ₀, the first portion 21, and the second portion 22 in the dispersion direction X are limited by limiting the first distance, the second distance, and the third distance to each be less than or equal to 2 times the port size.

As is apparent from the above description about the liquid crystal on silicon 4 and the pixel region 42, the diffraction deflection angle range that can be supported by the pixel region 42 in the first direction is much smaller than the diffraction deflection angle range that can be supported in the second direction. Therefore, in the wavelength selective switch 1 provided by the embodiment of the application, the diffraction deflection angle of the liquid crystal on silicon 4 in the dispersion direction X can be limited by limiting the first distance, the second distance and the third distance to be less than or equal to 2 times of port sizes, so that the requirement on the diffraction deflection angle range of the liquid crystal on silicon 4 in the dispersion direction X can be reduced while the compactness of port arrangement in the optical fiber array 2 is ensured, and the port insertion loss is reduced and the performance of the wavelength selective switch 1 is improved.

The various arrangements of the optical fiber array 2 will be described by way of example with reference to the accompanying drawings, and the advantages and principles that can be brought about by the optical fiber array 2 will be described with reference to the wavelength selective switch 1 employing the optical fiber array 2.

Referring to fig. 10, in order to describe the positions and arrangements of the first port D ₀ and the second port (D ₁ to D _N) in the optical fiber array 2, the port size is set to p. And a coordinate system is established by taking the optical path center O as an origin, taking the first reference line L ₁ as an X coordinate axis and the second reference line L ₂ as a Y coordinate axis, wherein the X coordinate axis is in a negative direction to the right and in a positive direction to the left, and the Y coordinate axis is in a positive direction upwards and in a negative direction downwards.

In order to facilitate understanding of diffraction and deflection of the incident light beam by the liquid crystal on silicon 4, in the following description of the working principle of the wavelength selective switch 1 in the down-wave scenario and the down-wave scenario, an example is given in which the incident light beam comprises optical signals of only one wavelength. And will be described in terms of a port plane optical path and a dispersion plane optical path, respectively. The port plane optical path is an optical path for controlling the deflection of the incident beam in the port direction Y of the optical fiber array 2 by the wavelength selective switch 1, and the dispersion plane optical path is an optical path for controlling the deflection of the incident beam in the dispersion direction X of the optical fiber array 2 by the wavelength selective switch 1.

Since the devices or apparatuses in the wavelength selective switch 1 are active in controlling the deflection of the incident light beam in the port direction Y of the optical fiber array 2 and are inactive in controlling the deflection of the incident light beam in the dispersion direction X of the optical fiber array 2, the devices or apparatuses are inactive in controlling the deflection of the incident light beam in the port direction Y of the optical fiber array 2 and are active in controlling the deflection of the incident light beam in the dispersion direction X of the optical fiber array 2. In order to better understand the principle of beam deflection, some non-functional devices or apparatuses are omitted in the port plane optical path and the dispersion plane optical path of the wavelength selective switch 1 provided in the embodiment of the present application.

As shown in fig. 10, in the optical fiber array 2 of the wavelength selective switch 1, all the optical fiber ports, that is, the first port D ₀, the first portion 21 and the second portion 22, are located on the same side of the second reference line L ₂, for example, on the side corresponding to the negative direction of the X coordinate axis, and for example, on the side corresponding to the positive direction of the X coordinate axis. The first port D ₀, the first portion 21 and the second portion 22 are aligned in the dispersion direction X. It should be noted that, herein, alignment in the dispersion direction X means that the orthographic projection positions on the first reference line L ₁ are the same, i.e., the X coordinates are the same, for example, alignment of the first port D ₀, the first portion 21, and the second portion 22 in the dispersion direction X means that the orthographic projection positions of the first port D ₀, the first portion 21, and the second portion 22 on the first reference line L ₁ are the same, and the X coordinates of the three are the same. When the orthographic projection positions on the first reference line L ₁ are different, it can be regarded as being offset in the dispersion direction X.

With the first port D ₀, the first portion 21, and the second portion 22 all located on the same side of the second reference line L ₂, and aligned in the dispersion direction X, the first distance, the second distance, and the third distance are all greater than 0 and equal. In addition, the first distance, the second distance, and the third distance are each less than or equal to 2 times the port size.

Illustratively, as shown in FIG. 10, the first port D ₀, the first portion 21, and the second portion 22 are offset by 0.5p in the negative direction of the X axis relative to the second reference line L ₂ (Y axis). In this case, the first port D ₀ has an X coordinate of-0.5 p and the Y coordinate of 0, and all the second ports (D ₁ to D _N) have an X coordinate of-0.5 p. The first distance, the second distance, and the third distance are all 0.5p.

The working principle of the wavelength selective switch 1 adopting the optical fiber array 2 in a down wave scene is as follows:

In the down-wave scenario, the first port D ₀ is an incident port for receiving an incident light beam, and any one of the second ports is a target port for outputting an outgoing light beam. After the incident light beam is incident from the first port D ₀, the incident light beam passes through the intermediate optical component 3 and irradiates the target pixel area on the liquid crystal on silicon 4, where the target pixel area is a pixel area 42 corresponding to the optical signal with the wavelength in the plurality of pixel areas 42 in the liquid crystal on silicon 4.

Fig. 11A is a schematic diagram of a port plane light path of a wavelength selective switch in a downlink scene provided by an embodiment of the present application, and fig. 12 is a positional relationship diagram of a diffracted light beam and an optical fiber array of the wavelength selective switch in the downlink scene provided by the embodiment of the present application, as shown in fig. 11A and fig. 12, a target pixel area is controlled by a liquid crystal on silicon 4 to form a blazed grating in a second direction, where the blazed grating can diffract and deflect an incident light beam in the second direction (corresponding to a port direction Y), and diffraction light beams of multiple diffraction orders arranged in the second direction, such as-2 order, -1 order, 0 order, +1 order, +2 order, and the like, are generated. Wherein +1 is the target order, and all diffraction orders except +1 are crosstalk orders. Meanwhile, the blazed grating formed by the liquid crystal on silicon 4 deflects the +1 (target order) diffraction beam in the port plane (the deflection angle is theta _y), the deflected +1 diffraction beam irradiates the optical fiber array 2 through the intermediate optical component 3, and the Y coordinate Y ₊₁ of the emergent position of the +1 diffraction beam in the optical fiber array 2 is the same as the Y coordinate Y _t of the target port (a second port), namely Y ₊₁＝Y_t.

With continued reference to fig. 11A and 12, the blazed grating formed by the lc-on-silicon 4 also deflects the diffracted light beams of the crosstalk order in the port plane, wherein the Y coordinate Y ₀ of the exit position of the 0 th order diffracted light beam in the optical fiber array 2 is identical to the Y coordinate Y _com of the first port D ₀, i.e., Y ₀＝Y_com, -the Y coordinate Y _-1 of the exit position of the 1 st order diffracted light beam in the optical fiber array 2 is identical to the Y coordinate Y _c of the other second port, and Y ₊₁ and Y _-1 are symmetrical about the X coordinate axis, i.e., Y _t＝-Y_c.

If the liquid crystal on silicon 4 uses a one-dimensional diffraction grating that can form a blazed grating only in the second direction, the diffraction beam formed by the blazed grating in the second direction is reflected in the dispersion plane by the mirror surface in the first direction, and the X-coordinate of the diffraction beam of each diffraction order is +0.5p, so that the diffraction beam cannot reach the target port (X-coordinate is-0.5 p) and exit.

Based on this, in the present embodiment, the liquid crystal on silicon 4 employs a two-dimensional diffraction grating of blazed grating that can be formed in both the first direction and the second direction.

Fig. 11B is a schematic diagram of a dispersion plane light path of a wavelength selective switch in a downlink scenario, where as shown in fig. 11B and fig. 12, a target pixel area controlled by a liquid crystal on silicon 4 also forms a blazed grating in a first direction, where the blazed grating is capable of diffracting and deflecting an incident light beam in the first direction (corresponding to a dispersion direction X), and diffraction light beams of multiple diffraction orders arranged in the first direction, such as-2 order, -1 order, 0 order, +1 order, +2 order, and the like, are generated. Wherein +1 is the target order, and all diffraction orders except +1 are crosstalk orders. Meanwhile, the blazed grating formed by the liquid crystal on silicon 4 deflects the +1 (target order) diffraction beam in the dispersion plane (the deflection angle is theta _x), the deflected +1 diffraction beam irradiates the optical fiber array 2 through the intermediate optical component 3, and the X coordinate X ₊₁ of the emergent position of the +1 diffraction beam in the optical fiber array 2 is identical to the X coordinate X _t of the target port (one second port), namely X ₊₁＝X_t = -0.5p.

With continued reference to fig. 11B and 12, the blazed grating formed by the lc-on-silicon 4 also deflects the diffracted beams of the crosstalk order in the dispersion plane, and in this embodiment, the diffracted beams of the crosstalk order are all projected to positions outside the ports in the optical fiber array 2. For example, as shown in fig. 12, the X coordinate X ₀ of the 0 th order diffracted beam at the exit position in the optical fiber array 2 is +0.5p, the X coordinate X _-1 of the-1 st order diffracted beam at the exit position in the optical fiber array 2 is +1.5p, and the X coordinate X ₊₂ of the +2 nd order diffracted beam at the exit position in the optical fiber array 2 is-1.5p.

Therefore, it can be seen that, in the wavelength selective switch 1 provided in this embodiment, only the diffracted light beams of the target order (+1 order) can exit through the target port, and the diffracted light beams of the crosstalk order cannot enter the optical fiber ports in the optical fiber array 2, so that the port isolation is improved, and the signal crosstalk between the ports is reduced.

The working principle of the wavelength selective switch 1 adopting the optical fiber array 2 in the uplink scene is as follows:

In the up-wave scenario, any one of the second ports is an incident port for receiving an incident light beam, which may be referred to as a source port, and the first port D ₀ is a target port for outputting an outgoing light beam.

Fig. 13A is a schematic diagram of a port plane light path in an uplink scene of a wavelength selective switch provided by an embodiment of the present application, and fig. 14 is a positional relationship diagram of a diffracted light beam and an optical fiber array in the uplink scene of the wavelength selective switch provided by the embodiment of the present application, as shown in fig. 13A and 14, a target pixel area is controlled by a liquid crystal on silicon 4 to form a blazed grating in a second direction, where the blazed grating is capable of diffracting and deflecting an incident light beam in the second direction (corresponding to a port direction Y), and diffraction light beams of a plurality of diffraction orders arranged in the second direction, such as-2 order, -1 order, 0 order, +1 order, and +2 order, are generated. Wherein +1 is the target order, and all diffraction orders except +1 are crosstalk orders. Meanwhile, the blazed grating formed by the liquid crystal on silicon 4 deflects the +1 order diffraction beam in the port plane (the deflection angle is theta _y), the deflected +1 order diffraction beam irradiates the optical fiber array 2 through the intermediate optical component 3, and the Y coordinate Y ₊₁ of the emergent position of the +1 order diffraction beam in the optical fiber array 2 is the same as the Y coordinate Y _com of the target port (the first port D ₀), namely Y ₊₁＝Y_com.

With continued reference to fig. 13A and 14, the blazed grating formed by the lc-on-silicon 4 also deflects the diffracted light beams of the crosstalk order in the port plane, wherein the Y coordinate Y ₀ of the 0 th order diffracted light beam at the exit position in the fiber array 2 is the same as the Y coordinate Y _c of one second port and Y ₀＝-Y_c, and the Y coordinate Y _-1 of the 1 st order diffracted light beam at the exit position in the fiber array 2 is the same as the Y coordinate of the other second port or is located outside the port.

Based on this, in the present embodiment, the liquid crystal on silicon 4 employs a two-dimensional diffraction grating of blazed grating that can be formed in both the first direction and the second direction. Fig. 13B is a schematic diagram of a dispersion plane optical path in a winding scene of the wavelength selective switch according to the embodiment of the present application, as shown in fig. 13B and 14, the liquid crystal on silicon 4 also forms a blazed grating in the first direction by controlling the pixel area 42, where the blazed grating is capable of diffracting and deflecting an incident light beam in the first direction (corresponding to the dispersion direction X), and may generate diffracted light beams of a plurality of diffraction orders arranged in the first direction, such as-2 order, -1 order, 0 order, +1 order, +2 order, and the like. Wherein +1 is the target order, and all diffraction orders except +1 are crosstalk orders. Meanwhile, the +1-order diffraction light beam is deflected in a dispersion plane (the deflection angle is theta _x) through the blazed grating formed by the liquid crystal on silicon 4, the deflected +1-order diffraction light beam irradiates the optical fiber array 2 through the intermediate optical component 3, the X coordinate X ₊₁ of the emergent position of the +1-order diffraction light beam in the optical fiber array 2 is identical to the X coordinate X _com of the target port (the second port), and the X ₊₁＝X_com = -0.5p.

With continued reference to fig. 13B and 14, the blazed grating formed by the liquid crystal on silicon 4 also deflects the diffracted light beams of the crosstalk order in the dispersion plane, and in this embodiment, the diffracted light beams of the crosstalk order are all projected at positions outside the ports, for example, the X coordinate X ₀ of the exit position of the 0 th order diffracted light beam in the optical fiber array 2 is +0.5p, the X coordinate X _-1 of the exit position of the 1 st order diffracted light beam in the optical fiber array 2 is +1.5p, and the X coordinate X ₊₂ of the exit position of the +2 nd order diffracted light beam in the optical fiber array 2 is-1.5p.

Therefore, it can be seen that, in the wavelength selective switch 1 provided in this embodiment, only the diffracted light beams of the target order (+1 order) can exit through the target port in the uplink scene, and the diffracted light beams of the crosstalk order cannot enter the optical fiber ports in the optical fiber array 2, so that the port isolation is improved, and the signal crosstalk between the ports is reduced.

As can be seen from the foregoing, in the wavelength selective switch 1 provided in the present embodiment, the optical fiber array 2 includes one first port D ₀ and a plurality of second ports (D ₁ to D _N) including the first portion 21 and the second portion 22 located on both sides of the first reference line L ₁. The first portion 21, the second portion 22 and the first port D ₀ are arranged in an "offset" and asymmetric "arrangement, all on the same side of the second reference line L ₂ and aligned in the dispersion direction X. The LCOS 4 adopts bilateral deflection and two-dimensional grating working modes in both the upper wave scene and the lower wave scene.

By designing in this way, on one hand, the double-side deflection adopted by the liquid crystal on silicon 4 can reduce the diffraction deflection angle required by the liquid crystal on silicon 4, and for the same number of ports, the port insertion loss can be reduced, or for the same port insertion loss, the doubling of the port number can be realized. On the other hand, the optical fiber array 2 adopts an offset and asymmetric arrangement mode, and combines the two-dimensional deflection realized by the two-dimensional grating of the liquid crystal on silicon 4, so that signal crosstalk generated by the fact that diffracted light beams with crosstalk orders of non +1 enter ports in the optical fiber array 2 can be effectively avoided, effective suppression of the signal crosstalk among the ports is realized, and isolation of a downlink scene and directivity of an uplink scene are improved.

In addition, by setting the first distance, the second distance and the third distance to be equal to 0.5p, the requirement on the diffraction deflection angle range of the liquid crystal on silicon 4 in the dispersion direction X can be reduced while the port arrangement compactness of the optical fiber array 2 is ensured, the port insertion loss can be reduced, and the performance of the wavelength selective switch 1 can be improved.

In the above-described embodiment, the first distance, the second distance, and the third distance are each 0.5p, but the optical fiber array 2 designed to be aligned in the dispersion direction X using the first port D ₀, the first portion 21, and the second portion 22 and to be located on the side of the second reference line L ₂ is not limited thereto, and the first distance, the second distance, and the third distance may each be any value less than or equal to 2p, for example, 0.2p, 0.4p, 0.6p, 0.8, 1p, 1.2p, 1.4p, 1.6p, 1.8p, 2p.

As can be seen from the above description about the working principle, the smaller the first distance, the second distance and the third distance, the lower the requirement for the diffraction deflection angle of the liquid crystal on silicon 4 in the dispersion direction X, so that the smaller the first distance, the second distance and the third distance should be selected as much as possible under the condition of meeting other requirements, so that the port insertion loss can be reduced and the diffraction efficiency can be improved.

In the optical fiber array 2 of the wavelength selective switch 1, as shown in fig. 15, the first port D ₀ is located at the intersection position of the second reference line L ₂ and the first reference line L ₁, that is, the optical path center O, and the first portion 21 and the second portion 22 are located on the same side of the second reference line L ₂, for example, on the side corresponding to the negative direction of the X coordinate axis, and for example, on the side corresponding to the positive direction of the X coordinate axis. And, the first portion 21 and the second portion 22 are aligned in the dispersion direction X. In this case, the first distance is equal to 0, and the second distance and the third distance are both greater than 0 and equal. And, the first distance, the second distance, and the third distance are each less than or equal to 2 times the port size.

Exemplary, as shown in FIG. 15, the first port D ₀ is located at the optical path center O, and the first portion 21 and the second portion 22 are offset in the negative direction of the X coordinate axisIn this case, the first port D ₀ has an X-coordinate of 0 and a Y-coordinate of 0, and all the second ports (D ₁ to D _N) have an X-coordinate of 0The distance between the first port D ₀ and the orthographic projection position of the first portion 21 on the first reference line L ₁ isThe first distance is 0, the second distance and the third distance are

It should be noted that the number of the substrates,When three optical fiber ports with the same size and round shape are arranged in an equilateral triangle, the minimum distance between one optical fiber port and the straight line where the other two optical fiber ports are located is the minimum distance.

In the down-wave scenario, the first port D ₀ is an incident port for receiving an incident light beam, and any one of the second ports is a target port for outputting an outgoing light beam.

Fig. 16A is a schematic diagram of a port plane light path of a wavelength selective switch in a downlink scene according to an embodiment of the present application, and fig. 17 is a positional relationship diagram of a diffracted beam and an optical fiber array of the wavelength selective switch in the downlink scene according to an embodiment of the present application, where an incident beam, as shown in fig. 16A and fig. 17, is incident from a first port D ₀, passes through an intermediate optical component 3, and then irradiates a target pixel area on a liquid crystal on silicon 4. The liquid crystal on silicon 4 controls the target pixel area to form a blazed grating in the second direction, the blazed grating can diffract and deflect the incident light beam, the +1-order (target-order) diffracted light beam is deflected in the port plane (the deflection angle is theta _y), the deflected +1-order diffracted light beam irradiates the optical fiber array 2 after passing through the intermediate optical component 3, and the Y coordinate Y ₊₁ of the emergent position of the +1-order diffracted light beam in the optical fiber array 2 is identical to the Y coordinate Y _t of the target port (one second port), namely Y ₊₁＝Y_t.

The blazed grating formed by the liquid crystal on silicon 4 also deflects the diffracted light beams of the crosstalk order in the port plane, wherein the Y coordinate Y ₀ of the exit position of the 0 th order diffracted light beam in the optical fiber array 2 is identical to the Y coordinate Y _com of the first port D ₀, i.e. Y ₀＝Y_com, -the Y coordinate Y _-1 of the exit position of the 1 st order diffracted light beam in the optical fiber array 2 is identical to the Y coordinate Y _c of the other second port, and Y ₊₁ and Y _-1 are symmetrical about the X coordinate axis, i.e. Y _t＝-Y_c.

If the liquid crystal on silicon 4 employs a one-dimensional diffraction grating capable of forming only a blazed grating in the second direction, the diffraction beam formed by the blazed grating in the second direction is reflected in the dispersion plane by the mirror surface in the first direction, and the X-coordinate of the diffraction beam of each diffraction order is 0, so that the diffraction beam cannot reach the target port (X-coordinate is) And (5) emergent.

FIG. 16B is a schematic view of a dispersion plane light path of a wavelength selective switch in a down-wave scenario, where as shown in FIG. 16B and FIG. 17, a target pixel area is controlled by a LCOS 4 to form a blazed grating in a first direction, the blazed grating is capable of diffracting and deflecting an incident light beam, a +1st-order (target-order) diffracted light beam is deflected in the dispersion plane (the deflection angle is θ _x), the deflected +1st-order diffracted light beam irradiates onto an optical fiber array 2 through an intermediate optical component 3, and an X coordinate X ₊₁ of an emergent position of the +1st-order diffracted light beam in the optical fiber array 2 is identical to an X coordinate X _t of a target port (a second port), that is

The blazed grating formed by the liquid crystal on silicon 4 also deflects the diffracted light beams of the crosstalk orders in the dispersion plane, wherein the X coordinate X ₀ of the exit position of the 0 th order diffracted light beam in the optical fiber array 2 is the same as the X coordinate X _com of the first port D ₀, X ₀＝X_com =0, the exit positions of the diffracted light beams of other crosstalk orders in the optical fiber array 2 are all located outside the port, for example, -the X coordinate X _-1 of the exit position of the 1 st order diffracted light beam in the optical fiber array 2 isLocated outside the port.

Fig. 18A is a schematic diagram of a port plane light path in a winding scene of a wavelength selective switch according to an embodiment of the present application, fig. 19 is a positional relationship diagram of a diffracted beam and an optical fiber array in the winding scene of the wavelength selective switch according to an embodiment of the present application, and as shown in fig. 18A and fig. 19, an incident beam is incident from a source port, passes through an intermediate optical component 3, and irradiates a target pixel area on a liquid crystal on silicon 4. The liquid crystal on silicon 4 controls the target pixel region to form a blazed grating in the second direction, the blazed grating is capable of diffracting and deflecting the incident light beam, the +1-order (target-order) diffracted light beam is deflected in the port plane (the deflection angle is θ _y), the deflected +1-order diffracted light beam irradiates onto the optical fiber array 2 through the intermediate optical component 3, and the Y coordinate Y ₊₁ of the emergent position of the +1-order diffracted light beam in the optical fiber array 2 is the same as the Y coordinate Y _com of the target port (the first port D ₀), that is, Y ₊₁＝Y_com.

The blazed grating formed by the liquid crystal on silicon 4 will also deflect the diffracted light beams of the crosstalk order in the port plane, wherein the Y coordinate Y ₀ of the exit position of the 0 th order diffracted light beam in the fiber array 2 is identical to the Y coordinate Y _c of one second port and Y ₀＝-Y_c, and the Y coordinate Y _-1 of the exit position of the-1 st order diffracted light beam in the fiber array 2 is identical to the Y coordinate of the other second port or is located outside the port.

If the liquid crystal on silicon 4 employs a one-dimensional diffraction grating capable of forming blazed gratings only in the second direction, the one-dimensional diffraction grating corresponds to a mirror surface in the first direction, so that the diffraction beams formed by the blazed gratings in the second direction are reflected in the dispersion plane, and the X-coordinate of the diffraction beams of each diffraction order isAnd therefore cannot reach the destination port (X coordinates 0) for exit.

Fig. 18B is a schematic diagram of a dispersion plane light path in an uplink scene of the wavelength selective switch provided by the embodiment of the present application, as shown in fig. 18B and 19, the liquid crystal on silicon 4 controls the target pixel area to form a blazed grating in the first direction, the blazed grating is capable of diffracting and deflecting the incident light beam, deflecting the +1st-order (target-order) diffracted light beam in the dispersion plane (the deflection angle is θ _x), the deflected +1st-order diffracted light beam irradiates onto the optical fiber array 2 through the intermediate optical component 3, and the X coordinate X ₊₁ of the emergent position of the +1st-order diffracted light beam in the optical fiber array 2 is the same as the X coordinate X _com of the target port (the second port), and X ₊₁＝X_com =0.

The blazed grating formed by the liquid crystal on silicon 4 also deflects the diffracted light beams of the crosstalk order in the dispersion plane, in this embodiment, the diffracted light beams of the crosstalk order are all projected at positions outside the ports in the optical fiber array 2, for example, the X coordinate X ₀ of the exit position of the 0 th order diffracted light beam in the optical fiber array 2 isThe X coordinate X _-1 of the emergent position of the-1 st-order diffraction beam in the optical fiber array 2 is

As can be seen from the foregoing, in the wavelength selective switch 1 provided in the present embodiment, the optical fiber array 2 includes a first port D0 and a plurality of second ports, and the plurality of second ports includes a first portion 21 and a second portion 22 located on two sides of the first reference line L ₁. The first portion 21, the second portion 22 and the first port D ₀ are arranged in an "offset, asymmetric" arrangement, the first port D ₀ being located at the optical path center O, the first portion 21 and the second portion 22 being located on the same side of the second reference line L ₂ and aligned in the dispersion direction X. The LCOS 4 adopts bilateral deflection and two-dimensional grating working modes in both the upper wave scene and the lower wave scene.

In addition, by setting the first distance to 0, the second distance and the third distance are both set toThe port arrangement compactness in the optical fiber array 2 can be ensured, the requirement on the diffraction deflection angle range of the silicon-based liquid crystal 4 in the dispersion direction X can be reduced, the port insertion loss can be reduced, and the performance of the wavelength selective switch 1 can be improved.

In the above embodiment, the first distance is 0, and the second distance and the third distance are bothHowever, for the optical fiber array 2 in which the first port D ₀ is located at the optical path center O, the first portion 21 and the second portion 22 are both located on the same side of the second reference line L ₂, and the alignment of the first portion 21 and the second portion 22 in the dispersion direction X is not limited thereto, it is satisfied that the distance between the orthographic projection positions of the first port D ₀ and the first portion 21 on the first reference line L ₁ is greater than or equal toAnd (3) obtaining the product. Exemplary, the first distance is 0, the second distance and the third distance are equal, the second distance and the third distance are greater than or equal toAnd any value less than or equal to 2p, such as 1p, 1.2p, 1.4p, 1.6p, 1.8p, 2p.

As can be seen from the above description about the working principle, the smaller the second distance and the third distance, the lower the requirement for the diffraction deflection angle of the liquid crystal on silicon 4 in the dispersion direction X, so the smaller the second distance and the third distance should be selected as much as possible under the condition of meeting other requirements, so that the port insertion loss can be reduced and the diffraction efficiency can be improved.

The embodiment of the present application provides a further wavelength selective switch 1, as shown in fig. 20, in the optical fiber array 2 of the wavelength selective switch 1, the first portion 21 is located on one side of the second reference line L ₂, for example, on one side corresponding to the negative direction of the X coordinate axis, and for example, on one side corresponding to the positive direction of the X coordinate axis. The first port D ₀ and the second portion 22 are both located on the second reference line L ₂, that is, the first port D ₀ is located at the optical path center O, the first port D ₀ and the second portion 22 are aligned in the dispersion direction X, and the first port D ₀ and the first portion 21 are disposed offset in the dispersion direction X. It can be seen that the X-coordinates of the first port D ₀ and the second portion 22 are the same and that the X-coordinates of the first port D ₀ and the first portion 21 are different. In this case, the first distance and the third distance are both equal to 0, and the second distance is greater than 0. And, the first distance, the second distance, and the third distance are each less than or equal to 2 times the port size.

Illustratively, as shown in FIG. 20, the first port D ₀ is located at the optical path center O, the second portion 22 is located on the second reference line L ₂, and the first portion 21 is offset by p in the negative direction of the X coordinate axis with respect to the second reference line L ₂. In this case, the X coordinates of the second ports in the first portion 21 are-p, the X coordinates of the first ports D ₀ are 0 and the Y coordinates are 0, and the X coordinates of the second ports in the second portion 22 are 0. The distance between the first port D ₀ and the orthographic projection position of the first portion 21 on the first reference line L ₁ is p, the first distance is 0, the second distance is p, and the third distance is 0.

In the down-wave scenario, the first port D ₀ is an incident port for receiving an incident light beam, and any one of the second ports is a target port for outputting an outgoing light beam. Fig. 21A is a schematic diagram of a port plane optical path in a downlink scene of a wavelength selective switch provided by an embodiment of the present application, fig. 21B is a schematic diagram of a dispersion plane optical path in a downlink scene of a wavelength selective switch provided by an embodiment of the present application, and fig. 22 is a positional relationship diagram of a diffracted beam and an optical fiber array in a downlink scene of a wavelength selective switch provided by an embodiment of the present application, where a portion (a) in fig. 21A, a portion (a) in fig. 21B, and a portion (a) in fig. 22 are cases where a target port is a second port in a first portion 21, and a portion (B) in fig. 21A, a portion (B) in fig. 21B), and a portion (B) in fig. 22 are cases where a target port is a second port in a second portion 22.

As shown in fig. 21A and 22, the incident light beam is incident from the first port D ₀, passes through the intermediate optical component 3, and then irradiates the target pixel region on the liquid crystal on silicon 4.

The liquid crystal on silicon 4 forms a blazed grating capable of diffracting and deflecting an incident light beam by controlling the target pixel region in the second direction, deflects the +1-order (target order) diffracted light beam in the port plane (the deflection angle is θ _y), irradiates the deflected +1-order diffracted light beam onto the optical fiber array 2 through the intermediate optical component 3, and the Y coordinate Y ₊₁ of the +1-order diffracted light beam at the exit position in the optical fiber array 2 is the same as the Y coordinate Y _t of the target port (one second port), that is, Y ₊₁＝Y_t.

If the liquid crystal on silicon 4 employs a one-dimensional diffraction grating capable of forming a blazed grating only in the second direction, the one-dimensional diffraction grating corresponds to a mirror surface in the first direction, so that the diffracted light beams formed by the blazed grating in the second direction are reflected in the dispersion plane, and the X-coordinate of the diffracted light beams of the respective diffraction orders is 0 and equal to the X-coordinate of the second port in the second portion 22.

Therefore, as shown in part (a) in fig. 21A, part (a) in fig. 21B, and part (a) in fig. 22, when the target port is the second port in the second portion 22, the liquid crystal on silicon 4 deflects the +1st-order diffracted light beam to the target port exit using the one-dimensional diffraction grating. For crosstalk orders, since the first portion 21 and the second portion 22 are staggered in the dispersion direction X, the diffracted beams of 0 th order and all negative orders do not enter the ports in the fiber array 2.

When the target port is the second port in the first portion 21, the liquid crystal on silicon 4 cannot make the +1 order (target order) diffracted beam reach the target port (X coordinate is-p) to exit using the one-dimensional diffraction grating. In this case, the liquid crystal on silicon 4 may employ a two-dimensional diffraction grating capable of forming blazed gratings in both the first direction and the second direction.

As shown in part (B) in fig. 21A, part (B) in fig. 21B, and part (B) in fig. 22, the liquid crystal on silicon 4 controls the target pixel region to also form a blazed grating capable of diffracting and deflecting the incident light beam, deflecting the +1st-order diffracted light beam in the dispersion plane (the deflection angle is θ _x), irradiating the deflected +1st-order diffracted light beam onto the optical fiber array 2 through the intermediate optical assembly 3, and the X coordinate X ₊₁ of the exit position of the +1st-order diffracted light beam in the optical fiber array 2 is the same as the X coordinate X _t of the target port (one second port), and X ₊₁＝X_t = -p.

The blazed grating formed by the liquid crystal on silicon 4 also deflects the diffracted light beams of the crosstalk orders in the dispersion plane, wherein the X coordinate X ₀ of the exit position of the 0 th order diffracted light beam in the optical fiber array 2 is the same as the X coordinate X _com of the first port D ₀, X ₀＝X_com =0, and the exit positions of the diffracted light beams of other crosstalk orders in the optical fiber array 2 are all located outside the port, for example, -the X coordinate X _-1 of the exit position of the 1 st order diffracted light beam in the optical fiber array 2 is +p, and is located outside the port.

Therefore, it can be seen that, in the wavelength selective switch 1 provided in this embodiment, only the diffracted light beams with the target order (+1 order) can exit through the target port, and for the case that the target port is the second port in the first portion 21, the liquid crystal on silicon 4 can implement two-dimensional deflection by using the two-dimensional diffraction grating, so that the diffracted light beams with the crosstalk order can be prevented from entering the optical fiber ports in the optical fiber array 2, which is favorable for improving the isolation of the ports and reducing the signal crosstalk between the ports. For the case that the target port is the second port in the second portion 22, the liquid crystal on silicon 4 may use a one-dimensional diffraction grating, and the diffracted light beams of 0 order and all negative orders cannot enter the optical fiber ports, so that the crosstalk problem caused by that the diffracted light beams of crosstalk order enter the optical fiber ports in the optical fiber array 2 can be effectively improved, thereby being beneficial to realizing the improvement of the port isolation and reducing the signal crosstalk between the ports. In addition, the silicon-based liquid crystal 4 adopts a one-dimensional diffraction grating, so that the port insertion loss condition can be further improved, and the performance of the wavelength selective switch 1 can be improved.

In some embodiments, when the target port is the second port in the second portion 22, the lc-on-silicon 4 may adopt a working manner of a two-dimensional diffraction grating, which may deflect the +1-order (target order) diffracted beam to the target port for emergence, and may avoid the crosstalk order of the diffracted beam from entering the optical fiber port, thereby being beneficial to improving the port isolation and reducing the signal crosstalk between the ports.

In the up-wave scenario, any one of the second ports is an incident port for receiving an incident light beam, which may also be referred to as a source port, and the first port D ₀ is a target port for outputting an outgoing light beam.

Fig. 23A is a schematic diagram of a port plane optical path in a winding scene of a wavelength selective switch provided by an embodiment of the present application, fig. 23B is a schematic diagram of a dispersion plane optical path in a winding scene of a wavelength selective switch provided by an embodiment of the present application, and fig. 24 is a positional relationship diagram of a diffracted beam and an optical fiber array in a winding scene of a wavelength selective switch provided by an embodiment of the present application, where a portion (a) in fig. 23A, a portion (a) in fig. 23B, and a portion (a) in fig. 24 are cases where a source port is a second port in a first portion 21, and a portion (B) in fig. 23A, a portion (B) in fig. 23B), and a portion (B) in fig. 24 are cases where a source port is a second port in a second portion 22.

As shown in fig. 23A and 24, the incident light beam is incident from the source port, passes through the intermediate optical assembly 3, and then irradiates the target pixel region on the liquid crystal on silicon 4.

The liquid crystal on silicon 4 controls the target pixel area to form a blazed grating in the second direction, the blazed grating can diffract and deflect the incident light beam, the +1-order (target order) diffracted light beam is deflected in the port plane (the deflection angle is theta _y), the deflected +1-order diffracted light beam irradiates onto the optical fiber array 2 through the intermediate optical component 3, and the Y coordinate Y ₊₁ of the emergent position of the +1-order diffracted light beam in the optical fiber array 2 is identical to the Y coordinate Y _com of the target port (the first port D ₀), namely Y ₊₁＝Y_com.

If the liquid crystal on silicon 4 employs a one-dimensional diffraction grating capable of forming a blazed grating only in the second direction, the diffraction beam formed by the blazed grating in the second direction is reflected in the dispersion plane by the mirror surface in the first direction, the X-coordinate of the diffraction beam of each diffraction order is 0 when the source port is the second port in the second section 22 and is the same as the target port (X-coordinate is 0), and the X-coordinate of the diffraction beam of each diffraction order is +p when the source port is the second port in the first section 21 and is different from the target port (X-coordinate is 0).

Therefore, as shown in part (a) of fig. 23A, part (a) of fig. 23B, and part (a) of fig. 24, when the second port of the second portion 22 is the source port, the liquid crystal on silicon 4 deflects the +1st-order diffracted beam to the target port for emission, and for the crosstalk order, since the first port D ₀ and the second portion 22 are staggered in the dispersion direction X, the 0 th-order diffracted beam and all the negative-order diffracted beams do not enter the ports of the optical fiber array 2.

When the source port is the second port in the first portion 21, the lc-on-silicon 4 cannot make the +1-order (target order) diffracted beam reach the target port (X-coordinate is 0) to exit using the one-dimensional diffraction grating. In this case, the liquid crystal on silicon 4 may employ a two-dimensional diffraction grating capable of forming blazed gratings in both the first direction and the second direction.

As shown in part (B) in fig. 23A, part (B) in fig. 23B, and part (B) in fig. 24, the liquid crystal on silicon 4 controls the target pixel region to also form a blazed grating capable of diffracting and deflecting the incident light beam, deflecting the +1 (target) order diffracted light beam in the dispersion plane (the deflection angle is θ _x), irradiating the deflected +1 order diffracted light beam onto the optical fiber array 2 through the intermediate optical component 3, and the X coordinate X ₊₁ of the +1 order diffracted light beam at the exit position in the optical fiber array 2 is the same as the X coordinate X _com of the target port (the first port D ₀), and X ₊₁＝X_com =0.

The blazed grating formed by the liquid crystal on silicon 4 also deflects the diffracted light beams of the crosstalk order in the dispersion plane, and in this embodiment, the diffracted light beams of the crosstalk order are all projected at positions outside the port, for example, X ₀ of the 0 th order diffracted light beam at the exit position in the optical fiber array 2 is +p, and X _-1 of the 1 st order diffracted light beam at the exit position in the optical fiber array 2 is +2p.

It can be seen that, in the wavelength selective switch 1 provided in this embodiment, only the diffracted light beam of the target order (+1 order) can exit through the target port in the uplink scene. For the case that the source port is the second port in the first portion 21, the liquid crystal on silicon 4 can adopt a two-dimensional diffraction grating to realize two-dimensional deflection, so that diffracted light beams with crosstalk orders can be prevented from entering the optical fiber ports in the optical fiber array 2, which is beneficial to improving directivity and reducing signal crosstalk between ports. For the case that the target port is the second port in the second portion 22, the liquid crystal on silicon 4 may use a one-dimensional diffraction grating, and the diffracted light beams of 0 order and all negative orders cannot enter the optical fiber ports, so that the crosstalk problem caused by that the diffracted light beams of crosstalk order enter the optical fiber ports in the optical fiber array 2 can be effectively improved, thereby being beneficial to realizing the improvement of directivity and reducing the signal crosstalk between the ports. In addition, the silicon-based liquid crystal 4 adopts a one-dimensional diffraction grating, so that the port insertion loss condition can be further improved, and the performance of the wavelength selective switch 1 can be improved.

In some embodiments, when the source grating is the second port in the second portion 22, the lc-on-silicon 4 may adopt a two-dimensional diffraction grating working manner, so that the +1-order (target order) diffraction beam can be deflected to the target port and exit, and the crosstalk order diffraction beam can be prevented from entering the optical fiber port, which is beneficial to improving the directivity and reducing the signal crosstalk between the ports.

As can be seen from the foregoing, in the wavelength selective switch 1 provided in this embodiment, the optical fiber array 2 includes a first port D ₀ and a plurality of second ports (D ₁ to D _N), the plurality of second ports (D ₁ to D _N) includes a first portion 21 and a second portion 22 located on two sides of the first reference line L ₁, the first portion 21, the second portion 22 and the first port D ₀ are arranged in an "offset and asymmetric" manner, the first port D ₀ and the second portion 22 are located on the second reference line L ₂, and the first portion 21 is located on one side of the second reference line L ₂. The lc-on-silicon 4 employs a bilateral deflection and two-dimensional grating mode of operation, and in some cases the lc-on-silicon 4 may employ a one-dimensional diffraction grating mode of operation.

By designing in this way, on one hand, the double-side deflection adopted by the liquid crystal on silicon 4 can reduce the diffraction deflection angle required by the liquid crystal on silicon 4, and for the same number of ports, the port insertion loss can be reduced, or for the same port insertion loss, the doubling of the port number can be realized. On the other hand, the optical fiber array 2 adopts an offset and asymmetric arrangement mode, and combines the working mode of the two-dimensional grating or the one-dimensional grating of the liquid crystal on silicon 4, so that the condition that signal crosstalk is generated when diffracted light beams with crosstalk orders enter ports in the optical fiber array 2 can be improved, the effective suppression of the signal crosstalk among the ports is realized, and the isolation of a lower wave scene and the directivity of an upper wave scene are improved.

In addition, by setting the first distance and the third distance to 0 and setting the second distance to p, the port arrangement compactness of the optical fiber array 2 can be ensured, the requirement on the diffraction deflection angle range of the liquid crystal on silicon 4 in the dispersion direction X can be reduced, the port insertion loss can be reduced, and the performance of the wavelength selective switch 1 can be improved.

In the above embodiment, the first distance and the third distance are 0, and the second distance is p, but for the optical fiber array 2 designed by using the first port D ₀ and the second portion 22 both located on the second reference line L ₂, the first portion 21 is located on the side of the second reference line L ₂, and is not limited thereto, as long as the distance between the orthographic projection positions of the first port D ₀ and the first portion 21 on the first reference line L ₁ is less than or equal to p, and for example, the first distance and the third distance are both 0, and the second distance may be any value less than or equal to 2p, for example, 0.5p, 1.5p, and 2p.

As can be seen from the above description of the working principle, the smaller the second distance, the lower the requirement for the diffraction deflection angle of the liquid crystal on silicon 4 in the dispersion direction X, so the smaller the second distance should be selected as much as possible under the condition that other requirements are satisfied.

The embodiment of the present application provides a further wavelength selective switch 1, as shown in fig. 25, in the optical fiber array 2 of the wavelength selective switch 1, the first port D ₀ is located on one side of the second reference line L ₂, for example, on one side corresponding to the negative direction of the X coordinate axis, and for example, on one side corresponding to the positive direction of the X coordinate axis. The first portion 21 and the second portion 22 are located on the other side of the second reference line L ₂ and the first portion 21 and the second portion 22 are aligned in the dispersion direction X, the distance of the first port D ₀ with respect to the second reference line L ₂ is equal to the distance of the first portion 21 with respect to the second reference line L ₂, in which case the first distance, the second distance and the third distance are all greater than 0 and equal. And, the first distance, the second distance, and the third distance are each less than or equal to 2 times the port size.

Illustratively, as shown in FIG. 25, the first port D ₀ is offset by p in the positive direction of the X axis, the first portion 21 and the second portion 22 are offset by p in the negative direction of the X axis as a whole, in which case the X coordinate of the first port D ₀ is +p and the Y coordinate is 0, and the X coordinates of all the second ports are-p. The first distance, the second distance, and the third distance are p.

In the down-wave scenario, the first port D0 is an incident port for receiving an incident light beam, and any one of the second ports is a target port for outputting an outgoing light beam. Fig. 26A is a schematic diagram of a port plane optical path of a wavelength selective switch in a downlink scene provided by an embodiment of the present application, fig. 26B is a schematic diagram of a dispersion plane optical path of the wavelength selective switch in the downlink scene provided by an embodiment of the present application, and fig. 27 is a positional relationship diagram of a diffracted beam and an optical fiber array of the wavelength selective switch in the downlink scene provided by an embodiment of the present application, as shown in fig. 26A, fig. 26B and fig. 27, an incident beam is incident from a first port D ₀, and then irradiates a target pixel area on a liquid crystal on silicon 4 through an intermediate optical component 3.

The liquid crystal on silicon 4 controls the target pixel area to form a blazed grating in the second direction, the blazed grating is capable of diffracting and deflecting the incident light beam, the +1-order (target-order) diffracted light beam is deflected in the port plane (the deflection angle is θ _y), the deflected +1-order diffracted light beam irradiates onto the optical fiber array 2 through the intermediate optical component 3, and the Y coordinate Y ₊₁ of the emergent position of the +1-order diffracted light beam in the optical fiber array 2 is identical to the Y coordinate Y _t of the target port (one second port), namely Y ₊₁＝Y_t.

If the liquid crystal on silicon 4 uses a one-dimensional diffraction grating that can form a blazed grating only in the second direction, the diffraction beam formed by the blazed grating in the second direction is reflected in the dispersion plane by the mirror surface in the first direction, and the X-coordinate of the diffraction beam of each diffraction order is-p, which is the same as the X-coordinate of the target port.

Therefore, in the down wave scene, the silicon-based liquid crystal 4 can deflect the +1-order diffraction beam to the target port to be emitted by adopting a one-dimensional diffraction grating, but the crosstalk order can enter the second port to form stronger signal crosstalk, and the isolation problem exists. This problem can be alleviated by optimizing the phase hologram algorithm of the liquid crystal on silicon 4, or by combining other means of crosstalk reduction.

From this, it can be seen that, in the wavelength selective switch 1 provided in this embodiment, the liquid crystal on silicon 4 can make the diffracted light beam of the target order (+1 order) exit through the target port by using the one-dimensional diffraction grating in the downlink scene, so that the port insertion loss can be further improved. The isolation problem can be alleviated by holographic optimization of the phase of the liquid crystal on silicon 4 or other crosstalk reduction means.

In the up-wave scenario, any one of the second ports is an incident port for receiving an incident light beam, which may be referred to as a source port, and the first port D ₀ is a target port for outputting an outgoing light beam. Fig. 28A is a schematic diagram of a port plane light path in a winding scene of a wavelength selective switch according to an embodiment of the present application, fig. 28B is a schematic diagram of a dispersion plane light path in a winding scene of a wavelength selective switch according to an embodiment of the present application, fig. 29 is a positional relationship diagram of a diffracted beam and an optical fiber array in a winding scene of a wavelength selective switch according to an embodiment of the present application, and as shown in fig. 28A, fig. 28B and fig. 29, an incident beam is incident from a source port, and then passes through an intermediate optical component 3 and irradiates a target pixel area on a liquid crystal on silicon 4.

The liquid crystal on silicon 4 controls the target pixel region to form a blazed grating in the second direction, the blazed grating is capable of diffracting and deflecting the incident light beam, the +1-order (target-order) diffracted light beam is deflected in the port plane (the deflection angle is θ _y), the deflected +1-order diffracted light beam irradiates onto the optical fiber array 2 through the intermediate optical component 3, and the Y coordinate Y ₊₁ of the emergent position of the +1-order diffracted light beam in the optical fiber array 2 is the same as the Y coordinate Y _com of the target port (the first port D ₀), that is, Y ₊₁＝Y_com.

If the liquid crystal on silicon 4 uses a one-dimensional diffraction grating that can form a blazed grating only in the second direction, the diffraction beam formed by the blazed grating in the second direction is reflected in the dispersion plane by the mirror surface in the first direction, and the X-coordinate of the diffraction beam of each diffraction order is p and the same as the X-coordinate of the target port (second port).

Therefore, in the uplink scenario, the liquid crystal on silicon 4 can deflect the +1-order diffracted beam to the target port to be emitted by adopting the one-dimensional diffraction grating, and for the crosstalk order, the first portion 21 and the second portion 22 are aligned in the dispersion direction X and are staggered from the first port D ₀, so that the diffracted beam of the crosstalk order cannot enter the port in the optical fiber array 2.

As can be seen from the foregoing, in the wavelength selective switch 1 provided in this embodiment, only the diffracted light beams of the target order (+1 order) can exit through the target port in the uplink scene, and the diffracted light beams of the crosstalk order cannot enter the fiber ports in the fiber array 2, so that the directivity is improved, and the signal crosstalk between the ports is reduced.

As can be seen from the foregoing, in the wavelength selective switch 1 provided in the present embodiment, the optical fiber array 2 includes one first port D ₀ and a plurality of second ports (D ₁ to D _N), and the plurality of second ports (D ₁ to D _N) includes the first portion 21 and the second portion 22 located on both sides of the first reference line L ₁. The first portion 21, the second portion 22 and the first port D ₀ are arranged in an "offset, asymmetric" arrangement, the first port D ₀ being located on one side of the second reference line L ₂, the first portion 21 and the second portion 22 being located on the other side of the second reference line L ₂, the first portion 21 and the second portion 22 being aligned in the dispersion direction X, the distance of the first port D ₀ from the second reference line L ₂ being equal to the distance of the first portion 21 from the second reference line L ₂. The LCOS 4 can adopt bilateral deflection and one-dimensional grating working modes in both an up-wave scene and a down-wave scene.

By designing in this way, on one hand, the double-side deflection adopted by the liquid crystal on silicon 4 can reduce the diffraction deflection angle required by the liquid crystal on silicon 4, and for the same number of ports, the port insertion loss can be reduced, or for the same port insertion loss, the doubling of the port number can be realized. On the other hand, the optical fiber array 2 adopts an offset and asymmetric arrangement mode, in an uplink scene, the silicon-based liquid crystal 4 adopts a one-dimensional diffraction grating to enable diffraction beams with the target order (+1) to be emitted through the target port, and signal crosstalk caused by the fact that diffraction beams with the crosstalk order which is not +1 enter the port in the optical fiber array 2 can be effectively avoided, effective suppression of the signal crosstalk between the ports is achieved, and the directivity of the uplink scene is improved. And the silicon-based liquid crystal 4 adopts a one-dimensional diffraction grating, so that the problem of port insertion loss can be solved.

In the up-wave scene, the silicon-based liquid crystal 4 adopts a one-dimensional diffraction grating to enable the diffraction light beams of the target order (+ 1) to be emitted through the target port, so that the port insertion loss can be further improved. The isolation problem can be alleviated by holographic optimization of the phase of the liquid crystal on silicon 4 or other crosstalk reduction means.

In some embodiments, in the downlink scenario, the liquid crystal on silicon 4 may use a two-dimensional diffraction grating, which not only deflects the +1-order (target order) diffracted beam to the target port for emergence, but also can avoid the crosstalk order diffracted beam from entering the optical fiber port, which is beneficial to improving the isolation and reducing the signal crosstalk between the ports.

In the above embodiment, the first distance, the second distance and the third distance are p, but for the optical fiber array 2 in which the first port D ₀ is located on one side of the second reference line L ₂ and the first portion 21 and the second portion 22 are located on the other side of the second reference line L ₂, and the alignment design of the first portion 21 and the second portion 22 in the dispersion direction X is not limited thereto, it is satisfied that the distance between the front projection positions of the first port D ₀ and the first portion 21 on the first reference line L ₁ is greater than or equal toAnd (3) obtaining the product. The first distance, the second distance, and the third distance are illustratively equal to or greater thanAnd any value less than or equal to 2p, e.g.,0.5p、p、1.5p、2p。

The above embodiments illustrate several arrangements of the optical fiber array 2 in the wavelength selective switch 1, but the embodiments of the present application are not limited thereto, and the arrangements of the optical fiber array 2 may include the following arrangements:

In some embodiments, the optical fiber array 2 may be arranged in such a manner that the orthographic projection positions of the first portion 21 and the second portion 22 on the first reference line L ₁ are the same, and the orthographic projection positions of the first port D ₀ and the first portion 21 on the first reference line L ₁ are different. The arrangement shown in fig. 17 and 25 belongs to this type of arrangement, which also includes other arrangements. Illustratively, the first port D ₀ is located on one side of the second reference line L ₂, the first portion 21 and the second portion 22 are located on the other side of the second reference line L ₂, the first portion 21 and the second portion 22 are aligned in the dispersion direction X, and the first distance is not equal to the second distance. Still another exemplary embodiment includes the first port D ₀, the first portion 21, and the second portion 22 being on the same side of the second reference line L ₂, the first portion 21 and the second portion 22 being aligned in the dispersion direction X, the first distance being unequal to the second distance. Still another exemplary, first port D ₀ is located on one side of second reference line L ₂, and first portion 21 and second portion 22 are located on second reference line L ₂;

For the above arrangement, in some embodiments, the spacing of the forward projection positions of the first port D ₀ and the first portion 21 on the first reference line L ₁ is greater than or equal to Multiple port sizes.

In some embodiments, the optical fiber array 2 may be arranged in such a way that the orthographic projection positions of the first portion 21 and the second portion 22 on the first reference line L ₁ are different, the orthographic projection position of the first port D ₀ on the first reference line L ₁ is the same as the orthographic projection position of the first portion 21, or the orthographic projection position of the first port D ₀ on the first reference line L ₁ is the same as the orthographic projection position of the second portion 22. The arrangement shown in fig. 20 belongs to this middle arrangement, and this arrangement also includes other arrangements. Illustratively, the first portion 21 is located on the second reference line L ₂, the second portion 21 is located on one side of the second reference line L ₂, and the first port D ₀ is aligned with the first portion 21 or the second portion 22 in the dispersion direction X. Still another example, neither the first port D ₀ nor the first portion 21 nor the second portion 22 is on the second reference line L ₂, the first portion 21 and the second portion 22 are on the same side or both sides of the second reference line L ₂, and the first port D ₀ is aligned with the first portion 21 or the second portion 22 in the dispersion direction X.

In some embodiments, the optical fiber array 2 may be arranged in a manner that the orthographic projection positions of the first port D ₀, the first portion 21, and the second portion 22 on the first reference line L ₁ are all different. Illustratively, one of the first port D ₀, the first portion 21, and the second portion 22 is located on the second reference line L ₂, and yet another illustratively, none of the first port D ₀, the first portion 21, and the second portion 22 is located on the second reference line L ₂, either on the same side or on both sides of the second reference line L ₂.

The technical effects and principles of the optical fiber array 2 in the above arrangement may be referred to the above description, and will not be described herein.

In some embodiments, the second ports in the first portion 21 and the second ports in the second portion 22 are all arranged at the same pitch, and the closest distance from the first reference line L ₁ in the first portion 21 is equal to the closest distance from the first reference line L ₁ in the second portion 22.

In order to achieve better double-sided deflection of the liquid crystal on silicon 4, the number of second ports in the first portion 21 and the second portion 22 is the same and symmetrically arranged with respect to the first reference line L ₁.

In some embodiments, the number of second ports in first portion 21 and second portion 22 is substantially the same, where substantially the same means that the difference in the number of the two does not exceed 5% of the greater number.

In the above embodiment, the second ports in the first portion 21 and the second portion 22 are each arranged in a straight line, and the straight line is parallel to the second reference line L ₂. On the one hand, the optical fiber ports which are arranged in a linear mode are easier to manufacture and ensure the position accuracy, so that the manufacturing difficulty of the optical fiber array 2 can be reduced, on the other hand, the optical fiber ports which are arranged in parallel with the second reference line L ₂ are more beneficial to port switching, the complexity of the port switching process can be reduced, the port switching can be realized more quickly and accurately, and the performance of the wavelength selective switch 1 can be improved.

Embodiments of the present application are not limited thereto and, for example, embodiments of the present application provide another wavelength selective switch in which an optical fiber array includes a first port and a plurality of second ports.

Wherein the first port is disposed on a first reference line.

It can be seen that the optical fiber array provided in this embodiment does not limit the arrangement of the first portion. The second ports in the first part can be arranged along a straight line parallel to the second reference line, can be arranged along a straight line not parallel to the second reference line, can be arranged along a regular or irregular curve, and can be arranged along a combination line, wherein the combination line can be formed by connecting a plurality of different straight lines, a plurality of different curves are formed by connecting a plurality of different curves, or the straight lines and the curves are formed by connecting a plurality of different curves.

The optical fiber array provided in this embodiment also does not limit the arrangement manner of the second portion. The second ports in the second part can be arranged along a straight line parallel to the second reference line, can be arranged along a straight line not parallel to the second reference line, can be arranged along a regular or irregular curve, and can be arranged along a combination line, wherein the combination line can be formed by connecting a plurality of different straight lines, a plurality of different curves are formed by connecting a plurality of different curves, or the straight line and the curve are formed by connecting a plurality of different curves.

In this case, the second distance is the maximum distance of the second port in the first portion relative to the second reference line, the third distance is the maximum distance of the second port in the second portion relative to the second reference line, and the first, second, and third distances are all less than or equal to 2 times the port size.

The wavelength selective switch adopting the optical fiber array can also improve the problem that the port crosstalk and the port insertion loss affect the port number expansion, and the working principle and the technical effects can be realized by referring to the description above, and the description is omitted here.

In the wavelength selective switch 1 provided in the embodiment of the present application, the intermediate optical component 3 is configured to optically adjust a light beam transmitted between the liquid crystal on silicon 4 and the optical fiber array 2, where the optical adjustment may include a wavelength division and a wavelength combination, and may further include at least one of polarization conversion, collimation, spot conversion, and change of direction of an optical path.

In the present embodiment, the intermediate optical component 3 includes one switching lens, three dispersion lenses, and a diffraction grating. As shown in fig. 11A, in the optical path corresponding to the port plane of the wavelength selective switch 1, the switching lens 31 is a basic structure of a 2f optical system, where the focal length of the switching lens 31 is f _sw, and the optical fiber array 2 and the liquid crystal on silicon 4 are respectively located on front and rear focal planes of the switching lens 31. By switching the lens 31, the optical path converts the deflection of the light beam by the liquid crystal on silicon 4 into a translation relative to the fiber ports in the fiber array 2.

As shown in fig. 11B, in the optical path corresponding to the dispersion plane of the wavelength selective switch 1, three dispersion lenses form the basic architecture of the 6f optical system, the first lens 32 forms the basic architecture of the 2f optical system, the second lens 33 and the third lens 35 form the 4f optical system, wherein the optical fiber array 2 is located at the front focal plane of the first lens 32, the diffraction grating 34 and the liquid crystal on silicon 4 are located at the front focal plane and the back focal plane of the third lens 35, respectively, and the focal length of the third lens 35 is f _d.

The deflection of the light beam by the liquid crystal on silicon 4 is converted into translation relative to the fiber ports in the fiber array 2 by the first lens 32, and the light beam is split into different wavelengths in the incident light beam by the second lens 33 and the third lens 35, dispersed to different positions of the liquid crystal on silicon 4 according to the wavelength, or the light beam with different wavelengths reflected by different positions of the liquid crystal on silicon 4 is combined to reconstruct the emergent light beam.

In the above embodiment, the wavelength selective switch 1 selects the liquid crystal on silicon 4 as the spatial light modulator, and the liquid crystal on silicon 4 has the characteristic of flexible Grid (Flex-Grid), and supports flexible allocation of the bandwidth of the wavelength selective switch channel. However, the embodiment of the present application is not limited thereto, and the wavelength selective switch provided in the embodiment of the present application may also use a Liquid Crystal (LC) device, a Micro-Electro-MECHANICAL SYSTEM (MEMS) device, or other devices made based on tunable Electro-optic medium as a spatial light modulator.

The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A wavelength selective switch, characterized in that it comprises an optical fiber array and a spatial light modulator; the optical fiber array comprises a first port and a plurality of second ports;

The plurality of second ports are divided into a first part and a second part located on both sides of the first reference line, and at least one of the first port, the first part and the second part is located on one side of the second reference line; when the first port is arranged at the center of the optical path, the first part and the second part are arranged asymmetrically relative to the first port;

In the optical fiber array, the distance between the first port and the second reference line is a first distance, the maximum distance between the second port in the first part and the second reference line is a second distance; the maximum distance between the second port in the second part and the second reference line is a third distance; the first distance, the second distance and the third distance are all less than or equal to 2 times the port size;

Among them, the center of the optical path is the position where the input light spot and the output light spot in the optical fiber array overlap when the spatial light modulator is used as a reflecting mirror; the first reference line is parallel to the dispersion direction, the second reference line is parallel to the port direction, and the intersection of the first reference line and the second reference line is the center of the optical path; the port size is the size of the first port in the dispersion direction.

2. The wavelength selective switch according to claim 1, characterized in that the first part and the second part each include at least two second ports, wherein the second ports in the first part are arranged along a straight line parallel to the second reference line, and the second ports in the second part are arranged along a straight line parallel to the second reference line.

3 . The wavelength selective switch according to claim 1 , wherein the first port is arranged on a first reference line.

4. The wavelength selective switch according to any one of claims 1 to 3, characterized in that the first port, the first portion and the second portion are located on the same side of the second reference line, and have the same orthographic projection position on the first reference line.

5. The wavelength selective switch according to claim 4, wherein the first port, the second port in the first part and the second port in the second part are at equal distances relative to the second reference line, which are all equal to 0.5 times the size of the port.

6 . The wavelength selective switch according to claim 2 , wherein the orthographic projection positions of the first portion and the second portion on the first reference line are the same, and the orthographic projection positions of the first port and the first portion on the first reference line are different.

7. The wavelength selective switch according to claim 6, wherein the distance between the first port and the first portion at the orthographic projection position on the first reference line is greater than or equal to times the port size.

8. The wavelength selective switch according to claim 6 or 7, characterized in that:

The first port is located on the second reference line; or

The first portion and the second portion are both located on the second reference line; or

The first port and the first portion are respectively located on two sides of the second reference line.

9. The wavelength selective switch according to claim 6 or 7, characterized in that:

The first port and the first portion are respectively located on both sides of the second reference line, and the first port and a second port in the first portion are equidistant from the second reference line.

10. The wavelength selective switch according to claim 9, wherein the distances between the first port and the second port in the first portion relative to the second reference line are both equal to the size of the port. or 0.5 times.

11. The wavelength selective switch according to claim 2, characterized in that:

The orthographic projection positions of the first part and the second part on the first reference line are different;

The first port is located at the same position as an orthographic projection of the first portion or the second portion on the first reference line.

12. The wavelength selective switch according to claim 11, characterized in that:

The first portion is located on the second reference line; or

the second portion is located on the second reference line; or

The first portion and the second portion are respectively located on two sides of the second reference line.

13 . The wavelength selective switch according to claim 11 , wherein a distance between the orthographic projection positions of the first portion and the second portion on the first reference line is equal to the port size.

14 . The wavelength selective switch according to claim 2 , wherein the orthographic projection positions of the first port, the first portion, and the second portion on the first reference line are all different.

15. The wavelength selective switch according to claim 14, wherein the first port is located at the center of the optical path;

The first portion and the second portion are located on the same side of the second reference line; or, the first portion and the second portion are located on two sides of the second reference line respectively.

16. The wavelength selective switch according to any one of claims 1 to 15, characterized in that the number of second ports in the first part and the number of second ports in the second part are equal;

In the port direction, the second ports in the first part and the second ports in the second part are arranged at the same interval;

The minimum distance between the second port in the first portion and the first reference line is equal to the minimum distance between the second port in the second portion and the first reference line.

17. The wavelength selective switch according to any one of claims 1 to 16, characterized in that the wavelength selective switch also includes an intermediate optical component located between the optical fiber array and the spatial light modulator; the intermediate optical component is used to optically adjust the light beam transmitted between the optical fiber array and the spatial light modulator.

18. The wavelength selective switch according to any one of claims 1 to 17, wherein the spatial light modulator is liquid crystal on silicon.

19. A node device, characterized by comprising at least one wavelength selective switch according to any one of claims 1 to 18.