JP4960294B2 - Wavelength selective switch - Google Patents

Description

  The present invention relates to a wavelength selective switch applicable to an optical communication system.

  While an increase in capacity of optical communication has progressed and transmission capacity has been increased by a wavelength division multiplexing (WDM) method, an increase in throughput of a path switching function in a node is strongly demanded. In the past, the path switching was mainly performed by an electrical switch after converting the transmitted optical signal to an electrical signal. However, taking advantage of the characteristics of the optical signal such as high speed and wide bandwidth, an optical switch, etc. A ROADM system that performs add / drop and the like using an optical signal as it is is introduced. Specifically, an optical signal is added / dropped at each node using a ring type network, and those that do not need to pass through the optical signal as it is, so that the node device is small and has low power consumption. is there. A wavelength selective switch (WSS) module is required as a device necessary for future development of these reconfigurable optical add / drop multiplexer (ROADM) systems.

  Conventionally, WSS using a bulk diffraction grating and a liquid crystal device is known (see, for example, Patent Document 1). 1 and 2 are diagrams showing the configuration of a WSS using such a bulk diffraction grating and a liquid crystal device. FIG. 1 is a perspective view of the WSS, and FIG. 2 is a cross-sectional view of the WSS. Light from the input / output optical fiber arrays 101 to 110 is deflected by the spherical mirror 112 and collimated to enter the diffraction grating 114. The light incident on the diffraction grating 114 is reflected at an emission angle corresponding to the wavelength, and enters the reflective liquid crystal device 115 via the lens 113 and the spherical mirror 112. The liquid crystal device 115 functions as a diffraction grating, and changes the traveling direction after reflection of light incident on the liquid crystal device 115. The light reflected by the liquid crystal device 115 returns to the input / output optical fiber arrays 101 to 110 via the spherical mirror 112, the lens 113 and the diffraction grating 114. Therefore, by controlling the diffraction effect by the liquid crystal device 115, it functions as a WSS that allows light to enter a desired input / output optical fiber array.

Japanese translation of PCT publication No. 2007-510957 (FIGS. 1 and 2) By Hector, Hector Optics II, September 2004, p88, p247

  However, the conventional wavelength selective switch (WSS) shown in FIGS. 1 and 2 has a problem that it is difficult to accurately lay out the input / output optical fiber array in a three-dimensional manner.

  In addition, there is a problem that the number of routes of the conventional WSS shown in FIGS. 1 and 2 is limited to about 1 × 9 (1 input 9 output, the same applies hereinafter). This is because, as will be described later, only a finite value with a small deflection angle by the reflective liquid crystal device can be obtained, and the distance between the optical fibers in the input / output optical fiber array can only be reduced to about 125 μm at the minimum. caused by.

  In other words, in the conventional WSS shown in FIGS. 1 and 2, the phase grating formed of the pixels of the reflective liquid crystal device (also referred to as a liquid crystal cell or a pixel in this specification) is in the switch axis direction (input / output optical fiber 101). By increasing the number of pixel divisions (number of pixels on which light is incident) per phase grating (to the array direction of ~ 110) and making the dependency of the deflection angle on the number of pixel divisions linear, the input / output optical fiber array can be accurately three-dimensionally It is necessary to facilitate layout. For this reason, since the phase grating pitch becomes wide, a large deflection angle cannot be obtained. FIG. 3 is a diagram showing the relationship between the length of the grating pitch per phase grating and the deflection angle. In the conventional WSS shown in FIGS. 1 and 2, for example, it is necessary to configure the phase grating so that the grating pitch length is 150 μm or more so that the dependency of the deflection angle on the number of divided pixels is linear. As shown in FIG. 3, the deflection angle is small in the region where the dependency of the deflection angle on the number of divided pixels is linear.

  Further, since the deflection angle of the reflective liquid crystal device is small and finite, the optical length between the input / output optical fiber array and the reflective liquid crystal device is increased in order to increase the number of outputs of the input / output optical fiber array. Need to be lengthened, and the device size of WSS becomes very large.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a wavelength selective switch that does not involve the difficulty of laying out an input / output optical fiber array in a three-dimensional manner with high accuracy. is there.

  Another object of the present invention is to provide a wavelength selective switch having a larger number of output paths than a conventional wavelength selective switch using a bulk diffraction grating and a liquid crystal device.

In order to achieve such an object, the present invention provides a wavelength selective switch according to claim 1, wherein the switch is at least one input waveguide, at least one output waveguide, the input waveguide, and the output. An optical waveguide substrate including an arrayed waveguide grating composed of a slab waveguide connected to a waveguide and an arrayed waveguide connected to the slab waveguide, and a spectrum for wavelength-separating a wavelength multiplexed optical signal emitted from the arrayed waveguide Means, a condensing lens, and the wavelength-separated optical signal collected by the condensing lens, each of which is independently phase-shifted, and the optical signal to which the phase shift is applied is the condensing lens and the spectroscopic means and a light deflecting means for reflecting to recombine the arrayed waveguide through the slab waveguide <214> is to distribute the wavelength-multiplexed optical signal input from the input waveguide Serial attached to the array waveguide, said arrayed waveguide is a plurality of arrayed waveguide of the waveguide length difference is zero, the spectroscopic means, emission wavelength-multiplexed signal emitted from the arrayed waveguide of the optical waveguide substrate It characterized the Turkey to the wavelength separating the wavelength-multiplexed signal in a plane perpendicular to and face and the optical waveguide substrate comprises a direction.

  The invention according to claim 2 is the wavelength selective switch according to claim 1, wherein the arrayed waveguide has an interval on the slab waveguide side smaller than an interval on the spectroscopic means side. .

  A third aspect of the present invention is the wavelength selective switch according to the first aspect, wherein the optical deflection unit includes two-dimensionally arranged elements that can give a phase shift to an incident optical signal. And at least three of the elements constitute a phase grating having a periodic structure in a direction in which the light deflecting means deflects.

  A fourth aspect of the present invention is the wavelength selective switch according to the third aspect, wherein a beam size of an optical signal incident on the optical deflecting unit is larger than a period of the periodic structure.

The invention according to claim 5 is the wavelength selective switch according to claim 1, wherein the wavelength-multiplexed optical signal emitted from the arrayed waveguide is polarized between the optical waveguide substrate and the spectroscopic means. It further comprises polarization separating means for separating, and beam size converting means for converting the beam sizes of the two wavelength-multiplexed optical signals subjected to polarization separation.

  As described above, according to the present invention, it is possible to provide a wavelength selective switch having a simple input / output waveguide configuration and a large number of output paths.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  4 to 6 are diagrams showing a configuration of a wavelength selective switch (WSS) according to an embodiment of the present invention. 4 to 6, X is a direction perpendicular to the optical waveguide substrate 210 and Y is a direction perpendicular to the optical waveguide substrate 210 and Y is a direction perpendicular to the optical waveguide substrate 210 in the optical waveguide substrate 210 included in the WSS 200 of the present embodiment. The traveling direction of the light wave in the waveguide substrate 210, that is, the optical axis is Z. 4 is a plan view of the XZ plane viewed from the Y-axis direction, FIG. 5 is a side view viewed from the X-axis direction, and FIG. 6 is a side view viewed from the Z-axis direction.

  The WSS 200 of this embodiment includes an optical waveguide substrate 210, a cylindrical lens 220, a polarization separation unit 230, a beam size conversion unit 240, a spectroscopic unit 250, a condensing lens 260, and an optical deflection unit 270. .

  On the optical waveguide substrate 210, an input / output waveguide 212, a slab waveguide 214 connected to the input / output waveguide 212, and an arrayed waveguide 216 connected to the slab waveguide 214 are fabricated.

  In this embodiment, there are a total of 21 input / output waveguides 212. The waveguide in the center is the input port In, and the waveguides formed on both sides of the input port In are the output ports # in order from the input port In. Called 1, 2, ..., 10 and # -1, -2, ..., -10.

  The slab waveguide 214 acts to distribute the light input from the input port In of the input waveguide 212 and couple it to the arrayed waveguide 216. In addition, the slab waveguide 214 outputs light input from the arrayed waveguide 216 according to the phase relationship between the light waves propagating through the arrayed waveguides. , 10, -1, -2, ..., -10.

  The arrayed waveguide 216 is a row of a plurality of waveguides having an optical path length difference of zero. The arrayed waveguide 216 enters the light from the slab waveguide 214 into the cylindrical lens 220 and couples the light from the cylindrical lens 220 to the slab waveguide 214.

  The cylindrical lens 220 acts so that the light emitted from the arrayed waveguide 216 enters the beam size conversion unit 240 without spreading in the Y-axis direction.

  The polarization separation unit 230 separates the light incident from the cylindrical lens 220 into two orthogonal polarization components (horizontal component and vertical component). The polarization separation unit 230 emits the two polarized light beams from different portions in the Y-axis direction. The light emitted from the polarization separation unit 230 enters the beam size conversion unit 240. A configuration example and the principle of the polarization separating means 230 will be described with reference to FIG. FIG. 7 shows a schematic configuration of a polarization beam displacer constituting the polarization separation unit. The polarization beam displacer can be made of a birefringent crystal (see, for example, Non-Patent Document 1), and includes a birefringent crystal (polarization separation crystal) 232 and a half-wave plate 234. The light incident on the birefringent crystal 232 of the polarization beam displacer has a horizontal polarization component above the output end face of the birefringent crystal 232 and a vertical polarization component below the output end face of the birefringent crystal 232. Emitted. Here, as shown in FIG. 7, when the half-wave plate 234 is provided in a plane perpendicular to the optical axis so that the main axis is 45 degrees from the horizontal direction, the vertical direction emitted from the birefringent crystal 232 Are converted into horizontal polarization components and output. Therefore, all the light incident on the polarization beam displacer is output as parallel light having a horizontal component. Since the behavior of the two adjacent beams is exactly the same, it is omitted in the following description and drawings.

  The beam size converter 240 acts to spread the light incident from the polarization separator 230 in the Y-axis direction. The present embodiment shows an example in which the beam size conversion unit 240 is configured by arranging two cylindrical lenses 242 and 244 in parallel to a plane including the X axis.

  The spectroscopic unit 250 acts to diffract the light incident from the beam size conversion unit 240 and separate the wavelength. The present embodiment shows an example in which the spectroscopic unit 250 is configured using a transmission type bulk diffraction grating 252. As a result of diffraction by the spectroscopic unit 250, each wavelength-separated light forms an interference fringe on the corresponding phase grating of the light deflecting unit 270.

  The condensing lens 260 acts to condense the light transmitted through the spectroscopic unit 250 onto the light deflecting unit 270. The present embodiment shows an example in which a cylindrical lens is used as the condenser lens 260.

  The optical deflecting unit 270 includes a phase control element that reflects incident light while deflecting it with a phase grating corresponding to each wavelength-separated optical signal, and couples it to the bulk diffraction grating 252 via the condenser lens 260. In this embodiment, the optical deflection unit 270 can be configured using a spatial phase modulator called LCOS (Liquid Crystal on Silicon). The LCOS is a reflective device in which liquid crystal elements (pixels) are arranged on the surface of a complementary metal-oxide semiconductor (CMOS). The liquid crystal element acts as a phase control element to give a phase difference to the incident optical signal, to form a phase grating, and to reverse the optical path.

  FIG. 8 is a diagram illustrating an outline of a light incident surface in the light deflecting unit 270 according to the present embodiment. As shown in the drawing, a plurality of pixels are arranged on a lattice on the light incident surface (XZ plane) of the light deflector 270. Each pixel can be controlled independently, and the amount of phase imparted to the light at each pixel can be controlled. Each optical signal wavelength-separated by the spectroscopic unit 250 is condensed by the condenser lens 270 on a corresponding pixel on the Z axis. That is, the light incident from the port In of the input / output waveguide 212 is wavelength-separated in the Z-axis direction in the light deflection unit 270.

FIG. 9 is a diagram illustrating a state in which a phase shift is given to light having a certain wavelength λ by the arrangement of certain pixels in the Z-axis direction of the light deflecting unit 270. In FIG. 9, if the pitch of one phase grating is d and the length of one side of each pixel is p (for example, 15 μm), d = n × p (n ≧ 3 integers: one pixel constituting the phase grating) Number). In this case, the deflection angle θ _d of light in the phase grating can be expressed as sin θ _d = λ / d. As described above with reference to FIG. 3, when the pitch d of the phase grating increases (that is, when n increases), the deflection angle dependency on the number of pixel divisions becomes linear, but the deflection angle decreases. On the other hand, when the pitch d of the phase grating is reduced, the deflection angle is increased, but the dependence of the deflection angle on the number of divided pixels is nonlinear. In this case, the interval between the input / output waveguides 212 is nonlinear and difficulty in layout occurs. However, the difficulty in layout is overcome by forming the input / output waveguides 212 on the optical waveguide substrate 210 as in this embodiment. can do. This is because the optical waveguide can be laid out flexibly by photolithography. In the present embodiment, the phase grating is configured with a small number of pixels such that the dependence of the deflection angle on the number of divided pixels is nonlinear, thereby enabling switching to more output ports.

  Here, with respect to the phase setting of each pixel constituting the phase grating on which light of a certain wavelength is incident (that is, pixels arranged in the X-axis direction), the difference between the phase setting amounts set in adjacent pixels is expressed as ε (FIG. 9), the relationship between the desired deflection angle θd and the phase set amount difference ε may be calculated in advance using a known calculation formula in consideration of various lenses, the arrangement of the optical waveguide substrate 210, and the like. It is possible (see Non-Patent Document 1). 9 illustrates a case where three pixels form a phase grating having a periodic structure in a direction in which the light deflecting unit 270 deflects light. However, as illustrated in FIG. You may comprise the phase grating which has a periodic structure.

  In the WSS 200 configured as described above, when a WDM optical signal in which optical signals of a plurality of wavelengths are multiplexed is incident from the port In, the WDM optical signal is guided through the slab waveguide 214 and distributed to the plurality of WDM optical signals. The waveguides constituting the arrayed waveguide 216 are coupled.

  After the WDM optical signal emitted from the arrayed waveguide 216 is converted into collimated light through the cylindrical lens 220, it enters the polarization separation unit 230 and is separated into a horizontal polarization component and a vertical polarization component. Are output as two WDM optical signals having the same polarization component.

  The two WDM optical signals emitted from the polarization separation unit 230 are each subjected to wavelength separation in the spectroscopic unit 250.

  Each optical signal subjected to wavelength separation in the spectroscopic unit 250 is condensed on a corresponding phase grating of the light deflecting unit 270 by the condenser lens 260. In FIG. 5, the optical signal enters the phase grating so that the Z axis is the wavelength axis. Optical signals of the same wavelength that have been wavelength-separated from the two WDM optical signals incident on the spectroscopic unit 250 from the polarization separation unit 230 are collected on the same phase grating.

  In each phase grating of the optical deflection unit 270, the optical signal is independently deflected for each wavelength and reflected so as to enter the spectroscopic unit 250 through the focus lens 260. The deflection angle of each optical signal is determined according to the period of the phase grating and the phase shift amount. In other words, the deflection angle can be controlled by controlling the period and phase shift amount of the phase grating corresponding to each WDM signal.

  The optical signals of the respective wavelengths incident again on the spectroscopic unit 250 are combined and coupled to the arrayed waveguide 216 via the beam size conversion unit 240, the polarization separation unit 230, and the cylindrical lens 220 again.

  The optical signals guided through the arrayed waveguide 216 are guided through the slab waveguide 214 and input to the output ports # 1, 2,..., 10, -1, -2,. Coupled to any of the output waveguides. The output port from which the optical signal is output can be arbitrarily set by controlling the deflection angle applied in the phase grating of the spectroscopic unit 250.

  FIG. 10 is a diagram for explaining an optical system in the optical selection switch (WSS) of the present embodiment. FIG. 10 corresponds to the WSS 200 of the above-described embodiment shown in FIGS. 4 to 6, but in FIG. 10, other elements except the optical waveguide substrate 210 and the optical deflecting unit 270 are shown for simplicity of explanation. Is omitted. In FIG. 10, the slab waveguide 214 included in the optical waveguide substrate 210 of the WSS 200 of the above embodiment is described as a functionally equivalent lens 214 ′ having a focal length f, and the deflecting unit 207 is used as a spatial light modulator. It is described. 10, S0 is an end surface of the input / output waveguide 212 (corresponding to the slab waveguide 214 and the connection surface in FIGS. 4 to 6), S12 is the main surface of the slab lens, and S3 is the slab waveguide 214 side of the arrayed waveguide 216. , S4 indicates the end surface of the arrayed waveguide 216 on the cylindrical lens 220 side (end surface of the optical waveguide substrate 210).

  A waveguide located at the center of the input waveguide 212 and corresponding to the input port In is made parallel to the Z axis. The lens 214 ′ is arranged so that the optical axis of the light incident from the input port In, that is, the principal ray passes through the center of the lens 214 ′.

  Similarly, the arrayed waveguide 216 is arranged so that the optical axis of the light incident from the input port In and the center of the arrayed waveguide 216 overlap. Further, in order to increase the number of WSS paths (number of input / output waveguides 212) and increase the integration, the distance d3 on the surface S3 of the arrayed waveguide 216 is configured to be narrower than the distance d4 on the surface S4.

  The light input from the input port In located at the center of the input waveguide 212 passes through the lens 214 ′ to become parallel light and is coupled to the arrayed waveguide 216. The optical axis of the incident light is perpendicular to the surface S3. Incident light is guided through the arrayed waveguide 216 and emitted from the end surface on the surface S4 side.

Incident light emitted from the arrayed waveguide 216 enters perpendicularly to the light incident surface of the spatial light modulator 207, is given a phase shift, and is reflected at a deflection angle (α _SLM ) corresponding to the phase shift. The light deflected and reflected by the spatial light modulator 207 enters the arrayed waveguide 216 again from the end surface of the surface S4. The reflected light at this time enters the arrayed waveguide 216 at an incident angle α ₄ (= α _SLM ).

The reflected light guided through the arrayed waveguides 216 is emitted from the end surface of the surface S3, the diffraction angle of alpha _3. FIG. 12 is a diagram showing the concept of the diffraction angle in the arrayed waveguide 216. As shown in FIG. 12, the incident angle α ₄ is converted into the outgoing angle α ₃ . The outgoing angle of the reflected light at this time is represented by α ₃ = arcsin (d ₄ / d ₃ × sin α ₄ ).

The reflected light emitted from the arrayed waveguide 216 enters the lens 214 ′ and is refracted and emitted. If the outgoing angle of the reflected light at this time is α ₁₂ , α ₁₂ = α ₄ −1 / f × h ₁₂ (h ₁₂ is the incident position of the incident light on the surface S12 of the lens 214 ′ and the reflected light Distance to the exit position).

The reflected light emitted from the lens 214 ′ is coupled to one of the input / output waveguides 212. At this time, in order to minimize the coupling loss, input and output waveguides 212 corresponding to the output port, it is desirable to make inclined by an angle alpha ₁₂ with respect to the Z-axis. The above relationship is briefly described as summarized in the equation in FIG.

  FIG. 11 is a diagram showing the interval and the inclination angle of the input / output waveguides in the present embodiment. The interval and the inclination angle of the output port increase nonlinearly according to the distance from the input port.

  FIG. 13 is a diagram for explaining the relationship between the pixels constituting the phase grating in the light deflecting unit 270 and the X axis (switch axis) of the beam size of light incident on the phase grating. As shown in FIG. 13, with respect to the beam size w (the beam diameter is 2w), the length p of one side of the pixel satisfies w> d, that is, light is incident on three or more consecutive pixels. The optical system is configured as follows. By setting in this way, the diffraction loss due to the phase grating can be reduced. For example, the beam size of the light incident on the phase grating of the light deflection unit 270 is adjusted by adjusting the focal length of the slab waveguide 214, that is, the lens 214 ′ to adjust the spread width of the light in the X-axis direction. Can do.

  In the present embodiment, the light diffracted by the spectroscopic unit 250 is wavelength-separated in the wavelength axis (Z-axis) direction of the light deflecting unit 270. Therefore, as shown in FIG. 15, as the light beam incident on the phase grating is thinner, crosstalk between adjacent light beams having different wavelengths can be reduced. In FIG. 15, w (GRID) is the width of the optical deflection unit 270 occupied by one WDM signal in the Z-axis or spectral axis direction, and w (BEAM) is the width of the incident monochromatic light beam. As shown in FIG. 15, by setting w (BEAM) <w (GRID), crosstalk between adjacent wavelengths can be reduced. In order to obtain a sufficiently low crosstalk and a wide transmission bandwidth, it is preferable that w (GRID) is about several times w (BEAM) or more. In FIG. 15, the width of the light deflection unit corresponding to the width of w (GRID) is shown as one pixel, but a plurality of pixels may be used for w (GRID).

  As described above, w (BEAM) is preferably set smaller than w (GRID). By the way, w (BEAM) is in an inversely proportional relationship with the beam size of the condenser lens 260 on the optical waveguide substrate 210 side. That is, in order to obtain a small w (BEAM), it is preferable to increase the beam size.

  FIG. 14 is a diagram illustrating a modification of the beam size conversion unit 240. As shown in FIG. 14, when the beam size conversion unit 240 is configured using two anamorphic prisms 246 and 248, the beam size conversion unit 240 is configured using two cylindrical lenses 242 and 244. Accordingly, the light spreading width in the Z-axis direction can be increased in the front stage of the condenser lens 260 with a short optical length, and the light beam incident on the phase grating of the light deflection unit 207 can be narrowed.

  Further, as shown in FIG. 14, a half-wave plate 234 constituting the polarization separation unit 230 may be disposed between the beam size conversion unit 240 and the diffraction grating 252.

  As described above, according to the present embodiment, the distance between the input / output ports can be reduced by using the waveguide instead of the input / output optical fiber array, and the wavelength selective switch shown in FIGS. A multi-port wavelength selective switch can be configured with the same optical path length. By creating an input optical system with a waveguide, it is determined by the accuracy of photolithography, and very precise alignment becomes possible.

  Furthermore, since the array waveguide pitch on the input / output waveguide side and the free space side of the arrayed waveguide grating can be set to different values, the deflection angle of the output light by the optical deflecting means can be enhanced. The optical path length can be shortened.

  In the present embodiment, the configuration using LCOS as the light deflecting unit 270 has been exemplified. However, the light deflecting unit 270 is not limited to LCOS, and is based on MEMS (Micro Electro-Mechanical Systems), piezo, electro-optic crystal, or the like. The same effect can be obtained even when a phase control element such as the above is used.

It is a figure which shows schematic structure of the conventional wavelength selective switch. It is a figure which shows schematic structure of the conventional wavelength selective switch. It is a figure which shows the relationship between the length of a grating pitch per phase grating, and a deflection angle. It is a figure which shows schematic structure of the wavelength selective switch concerning one Embodiment of this invention. It is a figure which shows schematic structure of the wavelength selective switch concerning one Embodiment of this invention. It is a figure which shows schematic structure of the wavelength selective switch concerning one Embodiment of this invention. It is a figure which shows schematic structure of the polarization beam displacer which comprises the polarization separation part of the wavelength selection switch concerning one Embodiment of this invention. It is a figure which shows the arrangement | sequence of the pixel in the optical deflection | deviation part of the wavelength selective switch concerning one Embodiment of this invention. It is a figure for demonstrating a mode that a phase shift is provided to the light of a certain wavelength (lambda) by the arrangement | sequence of a pixel in the optical deflection | deviation part of the wavelength selective switch concerning one Embodiment of this invention. It is a figure for demonstrating the optical system in the optical selection switch of one Embodiment of this invention. It is a figure which shows the space | interval and inclination angle of the input-output waveguide in one Embodiment of this invention. It is a figure which shows the conversion concept of the diffraction angle by the array waveguide in one Embodiment of this invention. It is a figure explaining the relationship between the pixel which comprises the phase grating in the optical deflection | deviation part of the wavelength selective switch of one Embodiment of this invention, and the beam size of the light which injects into a phase grating. It is a figure which shows the modification of the beam size conversion part of the wavelength selective switch of one Embodiment of this invention. It is a figure for demonstrating the relationship between the pixel size in the optical deflection | deviation part of the wavelength selective switch of one Embodiment of this invention, and the beam size of the incident light.

Explanation of symbols

DESCRIPTION OF SYMBOLS 200 Wavelength selection switch 210 Optical waveguide circuit 212 Input / output waveguide 214 Slab waveguide 216 Array waveguide 220 Cylindrical lens 230 Polarization separation part 232 Polarization separation crystal 234 1/2 wavelength plate 240 Beam size conversion part 242,244 Cylindrical lens 246,248 Anamorphic prism 250 Spectrometer 252 Bulk diffraction grating 260 Condensing lens 270 Light deflector, LCOS
272 pixels

Claims (5)

An optical including an arrayed waveguide grating comprising at least one input waveguide, at least one output waveguide, a slab waveguide connected to the input and output waveguides, and an arrayed waveguide connected to the slab waveguide A waveguide substrate;
Spectroscopic means for wavelength-separating the wavelength multiplexed optical signal emitted from the arrayed waveguide;
A condenser lens;
A phase shift is independently applied to the wavelength-separated optical signal collected by the condenser lens, and the optical signal to which the phase shift is applied is applied to the arrayed waveguide through the condenser lens and the spectroscopic means. A light deflecting means for reflecting so as to recombine,
The slab waveguide distributes the wavelength multiplexed optical signal input from the input waveguide and couples it to the arrayed waveguide;
The arrayed waveguide is a plurality of waveguide rows having a waveguide length difference of 0,
The spectral means includes wavelength-separating the wavelength-multiplexed signal in a plane that includes the emission direction of the wavelength-multiplexed signal emitted from the arrayed waveguide of the optical waveguide substrate and is perpendicular to the optical waveguide substrate. Select switch.   2. The wavelength selective switch according to claim 1, wherein the arrayed waveguide has an interval on the slab waveguide side smaller than an interval on the spectroscopic means side.   The light deflecting means includes two-dimensionally arranged elements capable of giving a phase shift to an incident optical signal, and at least three of the elements are in a direction <x direction> in which the light deflecting means is deflected. The wavelength selective switch according to claim 1, wherein the phase grating has a periodic structure.   4. The wavelength selective switch according to claim 3, wherein a beam size of an optical signal incident on the optical deflecting unit is larger than a period of the periodic structure. Between the optical waveguide substrate and the spectroscopic means,
Polarization separation means for polarization separating the wavelength-multiplexed optical signal emitted from the arrayed waveguide;
2. The wavelength selective switch according to claim 1, further comprising: a beam size converting unit that converts a beam size of the two wavelength-multiplexed optical signals subjected to polarization separation.

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