CN102253448A - Method for realizing uniform polarization compensation of array waveguide grating - Google Patents

Abstract

The invention discloses a method for realizing uniform polarization compensation by an arrayed waveguide grating. The optical path difference is jointly determined by the optical path difference of the arrayed waveguide area and the slab waveguide area. The arrayed waveguide is compensated by using different diffraction orders for the two polarization states in the arrayed waveguide area and combining the geometric birefringence properties of the slab waveguide area. Geometric birefringence properties of the region. The geometry of the slab waveguide region and the arrayed waveguide region is jointly determined by the selected waveguide material, waveguide structure and polarization dispersion requirements for each channel wavelength. The invention realizes uniform polarization dispersion compensation for each output channel wavelength of the arrayed waveguide grating, and solves the problems of uniform polarization dispersion compensation that cannot be realized by the polarization dispersion compensation method and the deterioration of device performance and complex structure. Arrayed waveguide gratings of various waveguide materials and various waveguide structures are especially suitable for silicon nanowire arrayed waveguide gratings with large geometric birefringence, and have the advantages of simple fabrication and low cost.

Description

A Method of Realizing Uniform Polarization Compensation with Arrayed Waveguide Grating

technical field

The invention relates to an arrayed waveguide grating, in particular to a method for realizing uniform polarization compensation by the arrayed waveguide grating.

Background technique

In the field of optical communication technology, there are many devices that realize the function of wavelength division multiplexing, mainly including multilayer dielectric thin film wavelength division multiplexing device (MDTFF), fiber Bragg grating type (FBG) wavelength division multiplexing device, etched diffraction grating type (EDG) ) wavelength division multiplexing devices and arrayed waveguide grating (AWG) wavelength division devices. But considering more wavelength channels and compatibility with silicon-based CMOS technology, arrayed waveguide grating is still one of the best choices. AWG has many advantages such as compact structure, easy integration, excellent performance and high reliability.

Polarization sensitivity has always been a critical issue in AWG applications. After the signal light is transmitted through an ordinary single-mode fiber, its polarization state will change randomly. Therefore, for optical devices on optical fiber lines, the problem of polarization insensitivity becomes very important. However, in practical applications, the optical waveguide on the optical path often exhibits different propagation characteristics for different incident polarization states, mainly because the propagation constants of the transverse electric mode (TE) and transverse magnetic mode (TM) in the waveguide are different. , which causes the image points of the TE mode and TM mode light to shift on the imaging plane, that is, a polarization-dependent wavelength shift occurs, thereby shifting the spectral response of the channel, which is the so-called polarization sensitivity. The polarization-dependent wavelength drift caused by this characteristic will have a significant impact on the transmission system, degrade the transmission signal, and increase the bit error rate of the optical communication system. Therefore, in order to increase the further application of AWG in optical communication systems, its polarization sensitivity must be eliminated.

At present, the polarization dispersion compensation technologies of AWG that have been reported at home and abroad mainly include: half-wave plate method, non-birefringent waveguide method, input and output plate area or array waveguide area adding polarization compensation area method, diffraction order matching method and polarization beam splitting technology wait. W. Bogaerts et al (W. Bogaerts, et al , A polarization-diversity wavelength duplexer circuit in silicon-on-insulator photonic wires," Opt. Express , vol. 15, no. 4, pp. 1567-1578, 2007. ) using a two-dimensional photonic crystal grating to separate the two polarization states of the fiber and couple them to the TE modes propagating in the silicon nanowire waveguide in two directions. The TE modes propagating in the two directions respectively pass through the same AWG in opposite directions, and finally Polarization insensitivity is achieved by using the same two-dimensional photonic crystal grating to couple the TE modes propagating in both directions back to the TE and TM modes propagating in the fiber. J.-J He et al. (J.-J. He, et al , “Polarization dispersion compensated AWG demultiplexer fabricated in single shallow etching step,” Electron. Lett., vol. 35, no. 9, pp. 737-738, 1999) introduce Polarization compensation area, so as to achieve the purpose of polarization compensation. Y. Inoue et al. (Y. Inoue, et al , "A novel birefringence compensating AWG design," OFC 2001, WB4-1, 2001) through the AWG array waveguide area pair Each arrayed waveguide uses two different core widths to change the optical path difference between TE and TM modes transmitted in the arrayed waveguide area, thereby achieving polarization insensitivity. National invention patent (ZL200610050488.4) "a polarization insensitive "Arrayed waveguide grating" realizes polarization dispersion compensation by using oblique Rowland circle (Rowland) incidence and the same diffraction order method. National invention patent (ZL03118878.8) "Polarization-independent folded arrayed waveguide grating" is achieved through folded array A Faraday rotator is placed in front of the reflector of the waveguide grating, so that the original TE (transverse electric mode) becomes TM (transverse magnetic mode), and the original TE becomes TM, so as to realize polarization independence. National invention patent (ZL200810059046.5) "A polarization-insensitive arrayed waveguide grating" separates the two polarization modes through the polarization beam splitter in the input slab waveguide, passes through two sets of arrayed waveguides with independent parameters, and finally passes through the polarization beam combiner in the output slab waveguide. The two polarization modes merge.

However, the implementation of the above-mentioned AWG polarization dispersion compensation technology mostly requires the addition of additional devices or additional process steps, which makes the manufacture of the device more complicated, the performance becomes lower, and the cost becomes higher. Especially for AWGs with large geometric birefringence, such as ultra-small silicon nanowire AWGs, the above method will become very difficult to achieve polarization dispersion compensation, which limits the application of this type of AWGs in optical communications .

Contents of the invention

In view of the deficiencies in the background technology, the purpose of the present invention is to provide a method for realizing uniform polarization compensation of arrayed waveguide gratings, so as to solve the problems of difficult polarization dispersion compensation and complicated structure of arrayed waveguide gratings with large birefringence in traditional polarization dispersion compensation technology .

The purpose of the present invention is achieved through the following technical solutions:

A method for achieving uniform polarization compensation with an arrayed waveguide grating. When light propagates from an input waveguide through an input slab waveguide area, an arrayed waveguide area, and an output slab waveguide area to an output waveguide, it passes through the total light corresponding to two adjacent waveguides in the arrayed waveguide area. The path difference is jointly determined by the optical path difference in the input slab waveguide area, the array waveguide area and the output slab waveguide area; there are birefringence differences between the respective two polarization states of the input slab waveguide area, array waveguide area, and output slab waveguide area ; After using different diffraction orders for the two polarization states in the arrayed waveguide area, the remaining polarization wavelength shift is jointly compensated by the input slab waveguide area and the output slab waveguide area; the waveguide upper cladding material of the input slab waveguide area and the output slab waveguide area The selection of the waveguide is determined by the waveguide material in the arrayed waveguide area, the waveguide structure and the requirements for polarization dispersion compensation in the design; The requirements for polarization dispersion compensation in the waveguide structure and design are jointly determined, so as to achieve the uniform polarization dispersion compensation requirements for each output channel wavelength of the arrayed waveguide grating.

，其中表示横电模TE在输入平板波导区和输出平板波导区的有效折射率且随波长而变化, 表示横电模TE在阵列波导区中的有效折射率且随波长而变化，表示横磁模TM在输入平板波导区和输出平板波导区的有效折射率且随波长而变化,

表示横磁模TM在阵列波导区中的有效折射率且随波长而变化；m为衍射级次且是大于零的正整数，i表示横电模TE和横磁模TM之间衍射级次的差异且是非零的整数。 The two polarization states in the arrayed waveguide region, that is, the transverse electric mode TE mode and the transverse magnetic mode TM mode, after adopting different diffraction orders, the remaining polarization wavelength drift is jointly compensated by the input slab waveguide region and the output slab waveguide region; that is : The length difference in the input slab waveguide area is ∆L ₀ , the length difference in the output slab waveguide area is ∆L , the length difference in the array waveguide area is ∆L _a , and the length difference between ∆L ₀ , ∆L and ∆L _a The relationship between and

,in Represents the effective refractive index of the transverse electric mode TE in the input slab waveguide region and the output slab waveguide region and varies with wavelength, represents the effective refractive index of the transverse electric mode TE in the arrayed waveguide region and varies with wavelength, represents the transverse magnetic mode TM The effective refractive index in the input slab waveguide region and the output slab waveguide region varies with wavelength,

Indicates the effective refractive index of the transverse magnetic mode TM in the arrayed waveguide region and changes with the wavelength; m is the diffraction order and is a positive integer greater than zero, and i indicates the diffraction order between the transverse electric mode TE and the transverse magnetic mode TM difference and is a non-zero integer.

The waveguide upper cladding material of the input slab waveguide area and the output slab waveguide area is the same or different from the waveguide upper cladding material of the arrayed waveguide area, and its selection is completely determined by the waveguide material in the arrayed waveguide area, the waveguide structure and The requirements for polarization dispersion compensation in the design are jointly determined.

After the waveguide material in the arrayed waveguide area, the waveguide structure, and the requirements for polarization dispersion compensation in the design are determined, the geometric shapes of the input slab waveguide area, output slab waveguide area, and arrayed waveguide area are determined by the central wavelength within the designed wavelength range λ ₀ , m and i are determined by the relation

决定。

Decide.

The angle α between the tangent line of the center of the boundary curve between the input slab waveguide area and the array waveguide area and the optical axis of the input slab waveguide area is an angle between 30°<α<90° and 90°<α<150°; the output plate The angle α between the tangent line of the center of the boundary curve of the waveguide area and the arrayed waveguide area and the optical axis of the output slab waveguide area is an angle between 30°<α<90° and 90°<α<150°, and the included angle The angle α is determined by the length difference ∆L ₀ of the input slab waveguide area and the distance between the center of the middle array waveguide in the array waveguide area and the line connecting the center of the adjacent array waveguide.

The beneficial effects that the present invention has are:

1. A method for implementing uniform polarization compensation of an arrayed waveguide grating disclosed in the present invention can fully compensate the wavelength shift of each output channel of the arrayed waveguide grating caused by the polarization state of the signal light, without adding additional devices and without changing the basic part of the AWG Under the premise of achieving uniform polarization compensation of each channel wavelength.

2. A method for realizing uniform polarization compensation of an arrayed waveguide grating disclosed in the present invention is applicable to various waveguide materials and waveguide structures with birefringence, especially for waveguide materials and waveguide structures with large geometric birefringence, For example, silicon nanoarray waveguide gratings based on SOI materials for optical interconnection.

Description of drawings

Fig. 1 is a schematic diagram of the principle structure of the present invention.

Fig. 2 is an enlarged view of the center of the middle arrayed waveguide in the arrayed waveguide region and the connecting line between the centers of adjacent arrayed waveguides.

FIG. 3 is an enlarged view of the output slab waveguide region in FIG. 1 .

Fig. 4 is a schematic diagram of a waveguide structure used in the input slab waveguide area and the output slab waveguide area.

Fig. 5 is a schematic diagram of a strip waveguide structure used in the arrayed waveguide region.

Fig. 6 is a schematic diagram of a ridge waveguide structure used in the arrayed waveguide region.

在上包层分别为空气、二氧化硅和SU-8聚合物的情况下随波长的变化情况。 Figure 7 is in Equation 5

The variation with wavelength when the upper cladding is air, silica and SU-8 polymer respectively.

FIG. 8 is an output spectrum diagram of an 8×8 uniform polarization compensation AWG designed by the method of the present invention.

FIG. 9 is a comparison diagram of polarization-related wavelength drift of each channel obtained under three different polarization compensation methods.

In the figure: 1, input waveguide, 2, input slab waveguide area, 3, array waveguide area, 4, output slab waveguide area, 5, output waveguide, 6, tangent line of the junction curve center of input slab waveguide area and array waveguide area, 7. The optical axis of the input slab waveguide area, 8. The diameter of the Rowland circle, 9. The Rowland circle where the end of the input waveguide is located, 10. The grating circle where the end of the array waveguide is located, with a radius of R, 11. The output slab waveguide area and the array waveguide 12. The connection line between a certain output waveguide and the center of the arrayed waveguide, 13. The optical axis of the output slab waveguide area, 14. The center of the middle arrayed waveguide in the arrayed waveguide area and the center of the adjacent arrayed waveguide connection.

Detailed ways

The present invention will be further described below in conjunction with drawings and embodiments.

和输出平板区4中的光程差

共同决定，其中是输入平板波导区2和输出平板波导区4中的有效折射率，

是阵列波导区3中的有效折射率，

、

和

分别是对应相邻阵列波导的光路在输入平板波导区2、阵列波导区3和输出平板波导区4中的长度差。输入平板波导区2、阵列波导区3和输出平板波导区4的各自的两偏振态模式之间均存在双折射差异；阵列波导区3中两种偏振态使用不同衍射级次后余下的偏振波长漂移由输入平板波导区2和输出平板波导区4共同补偿；输入平板波导区2和输出平板波导区4的波导上包层材料的选取由阵列波导区3中的波导材料、波导结构和设计中对偏振色散补偿的要求共同决定；输入平板波导区2、输出平板波导区4和阵列波导区3的几何形状由阵列波导区3中的波导材料、波导结构和设计中对偏振色散补偿的要求共同决定，从而达到对阵列波导光栅各输出通道波长的均匀偏振色散补偿要求。 As shown in accompanying drawing 1 and accompanying drawing 3, the method described in the present invention is: light from input waveguide 1 sequentially passes through input slab waveguide area 2, array waveguide area 3 and output slab waveguide area 4 and passes through array when propagating to output waveguide 5 The total optical path difference corresponding to two adjacent waveguides in the waveguide area 3 is composed of the optical path difference in the input slab waveguide area 2 and the optical path difference in the arrayed waveguide area 3

and the optical path difference in the output plate region 4

jointly decide, where is the effective refractive index in the input slab waveguide region 2 and the output slab waveguide region 4,

is the effective refractive index in the arrayed waveguide region 3,

,

and

are respectively the length differences of the optical paths corresponding to adjacent arrayed waveguides in the input slab waveguide region 2 , the arrayed waveguide region 3 and the output slab waveguide region 4 . There are birefringence differences between the respective two polarization modes of the input slab waveguide region 2, the array waveguide region 3 and the output slab waveguide region 4; the remaining polarization wavelengths after using different diffraction orders for the two polarization states in the array waveguide region 3 Drift is jointly compensated by the input slab waveguide region 2 and the output slab waveguide region 4; the selection of cladding materials on the waveguides of the input slab waveguide region 2 and the output slab waveguide region 4 is determined by the waveguide material in the arrayed waveguide region 3, the waveguide structure and the design process. The requirements for polarization dispersion compensation are jointly determined; the geometric shapes of the input slab waveguide region 2, output slab waveguide region 4 and array waveguide region 3 are jointly determined by the waveguide material in the array waveguide region 3, the waveguide structure and the requirements for polarization dispersion compensation in the design. Determined, so as to meet the requirement of uniform polarization dispersion compensation for each output channel wavelength of the arrayed waveguide grating.

According to the present invention, the waveguide upper cladding material of the input slab waveguide region 2 and the output slab waveguide region 4 is the same or different from the waveguide upper cladding material of the arrayed waveguide region 3, and its selection is completely determined by the arrayed waveguide region 3. The waveguide material, waveguide structure, and design requirements for polarization dispersion compensation are jointly determined. The waveguide structure adopted by the input slab waveguide area 2 and the output slab waveguide area 4 is shown in FIG. 4 , and the waveguide structure of the arrayed waveguide area 3 is a structure in FIG. 5 or FIG. 6 . The waveguide core material and lower cladding material in accompanying drawing 4 are the same as the waveguide core material and lower cladding material in accompanying drawing 5 and accompanying drawing 6, and the waveguide upper cladding material in accompanying drawing 4 is the same as accompanying drawing 5 and accompanying drawing 6 The cladding materials on the waveguides in Fig. 6 are the same or different. The waveguide material in the arrayed waveguide area 3 refers to the waveguide core material, upper cladding material and lower cladding material selected in the design, and the waveguide structure refers to the core structure of the waveguide selected, that is, strip (Fig. 5) or ridge (Figure 6), the requirements for polarization dispersion compensation in the design refer to the index conditions used in the design.

，且

，输出平板波导区4引入的长度差为且

，其中，d为阵列波导区3中的中间阵列波导的中心与相邻的阵列波导中心的连线14的距离，即附图2所示(注意，若阵列波导数目为奇数则是最中间一根阵列波导为中间阵列波导，若阵列波导数目为偶数则是最中间两跟阵列波导之一为中间阵列波导，图示所选的相邻阵列波导为右边相邻阵列波导)，

为输入平板波导区的光轴7和罗兰圆的直径8之间的夹角，

是某一输出波导与阵列波导中心的连线12和输出平板波导区的光轴13之间的夹角，即附图3所示(图3中，为了示意明白，标注14代表的连线有一个移位)，则该阵列波导光栅的衍射方程为： According to the specific embodiment of the present invention and in conjunction with Fig. 1, Fig. 2 and Fig. 3, the length difference introduced by the input slab waveguide region 2 is

,and

, the length difference introduced by the output slab waveguide region 4 is and

, where d is the distance between the center of the middle arrayed waveguide in the arrayed waveguide region 3 and the connecting line 14 between the centers of the adjacent arrayed waveguides, as shown in Figure 2 (note that if the number of arrayed waveguides is an odd number, then the middle one The root array waveguide is the middle array waveguide. If the number of array waveguides is even, one of the two most middle array waveguides is the middle array waveguide. The adjacent array waveguide selected in the figure is the right adjacent array waveguide),

is the angle between the optical axis 7 of the input slab waveguide region and the diameter 8 of the Rowland circle,

is the angle between the line 12 between a certain output waveguide and the center of the arrayed waveguide and the optical axis 13 of the output slab waveguide area, as shown in Figure 3 (in Figure 3, for the sake of clarity, the line represented by label 14 has A shift), then the diffraction equation of the arrayed waveguide grating is:

(1)

(1)

是输入平板波导区2和输出平板波导区4中的有效折射率，是阵列波导区3中的有效折射率，

是对应相邻阵列波导的光路在阵列波导区3中的长度差，m是某一整数衍射级次，

是对应的某一波长。根据本发明所述，对波导中的TE和TM模采用不同的衍射级次，即 in,

is the effective refractive index in the input slab waveguide region 2 and the output slab waveguide region 4, is the effective refractive index in the arrayed waveguide region 3,

is the length difference of the optical paths corresponding to adjacent arrayed waveguides in the arrayed waveguide region 3, m is a certain integer diffraction order,

is the corresponding wavelength. According to the present invention, different diffraction orders are adopted for the TE and TM modes in the waveguide, namely

(2)

(2)

(3)

(3)

，有

，中心波长偏振不敏感的条件为

，则平板波导区和阵列波导区中的长度差

和可表示为 Wherein, i is a non-zero integer and represents the difference in diffraction order between TE and TM modes, and subscripts e and m represent TE and TM modes, respectively. For the center wavelength within the designed wavelength range

,have

, the central wavelength polarization insensitive condition is

, then the length difference between the slab waveguide region and the arrayed waveguide region

and can be expressed as

(4)

(4)

It can be seen from formula 4 that once the diffraction orders m and i are determined, the geometry of the input slab waveguide region 2, output slab waveguide region 4 and array waveguide region 3 will also be determined.

According to the present invention, what is to be realized is uniform polarization compensation, so after the center wavelength is compensated, the compensation of other channel wavelengths needs to be considered. According to Formula 2, Formula 3 and Formula 4, it can be seen that for a certain output channel , the wavelength shift corresponding to the two polarization states is:

(5)

(5)

表示TE模和TM模之间总的折射率差异，而是输入平板波导区2和输出平板波导区4中的群折射率，

是阵列波导区3中的群折射率。从公式5可以看出，波长偏移 in,

represents the total refractive index difference between the TE mode and the TM mode, while is the group refractive index in the input slab waveguide region 2 and the output slab waveguide region 4,

is the group refractive index in the arrayed waveguide region 3 . From Equation 5 it can be seen that the wavelength shift

有关，而

又取决于输入平板波导区2和输出平板波导区4中TE和TM模的有效折射率与群折射率、阵列波导区3中TE和TM模的群折射率和补偿系数γ，因此对各个波长最小化

也就最小化了偏振波长漂移。根据

的特征，在设计中选定了阵列波导区3的波导材料后，实现

的最小化有如下可选择方式：调整输入平板波导区2和输出平板波导区4中TE和TM模的有效折射率，即选择合适的输入平板波导区2和输出平板波导区4的上包层材料；偏振补偿系数γ，而γ主要由公式4确定，即由衍射级次m和TE与TM之间的衍射级次差i决定，那就是说，实现均匀偏振补偿需要优化m与i；调整阵列波导区3中传输的TE和TM模的群折射率，即波导的结构。 main and

related to

It depends on the effective refractive index and group refractive index of TE and TM modes in the input slab waveguide region 2 and the output slab waveguide region 4, the group refractive index and compensation coefficient γ of the TE and TM modes in the arrayed waveguide region 3, so for each wavelength minimize

Polarization wavelength drift is also minimized. according to

The characteristics of , after selecting the waveguide material of the arrayed waveguide region 3 in the design, realize

There are the following optional ways to minimize the slab waveguide region 2 and the output slab waveguide region: adjust the effective refractive index of the TE and TM modes in the slab waveguide region 2 and the output slab waveguide region 4, that is, to select the appropriate upper cladding layer of the input slab waveguide region 2 and the output slab waveguide region 4 Material; polarization compensation coefficient γ, and γ is mainly determined by formula 4, that is, determined by the diffraction order m and the diffraction order difference i between TE and TM, that is to say, to achieve uniform polarization compensation, m and i need to be optimized; adjust The group refractive index of the TE and TM modes transmitted in the arrayed waveguide region 3, that is, the structure of the waveguide.

According to the present invention, the angle α between the tangent line 6 of the center of the boundary curve between the input slab waveguide region and the arrayed waveguide region and the optical axis of the input slab waveguide region 2 is 30°<α<90° and 90°<α<150° A certain angle in; the angle α between the tangent line 11 of the center of the boundary curve between the output slab waveguide area and the arrayed waveguide area and the optical axis of the output slab waveguide area 4 is 30°<α<90° and 90°<α<150° an angle in . Wherein, the tangent 6 of the center of the boundary curve between the input slab waveguide area and the arrayed waveguide area is obtained by making a tangent line at the tangent point of the Rowland circle 9 where the end of the input waveguide is located and the grating circle 10 where the end of the array waveguide is located, and the included angle α is determined by the length difference of the input slab waveguide region 2 and the center of the middle arrayed waveguide in the arrayed waveguide region and adjacent

。 The distance d between the center line 14 of the arrayed waveguide is determined and satisfies the relation

.

According to the present invention, achieving a good uniform polarization compensation effect is the result of selecting appropriate waveguide upper cladding material, polarization compensation coefficient γ and waveguide structure of the input slab waveguide region 2 and output slab waveguide region 4 .

Next, we will further illustrate the present invention with a specific case:

在上包层分别为空气、二氧化硅和SU-8聚合物的情况下随波长的变化情况，从图中可以看出，选择SU-8作为Si波导的上包层可以得到较小的

值，进而得到较好的偏振补偿效果。另外，在SU-8作为上包层的情况下，TM衍射级次为m=16，TE和TM模的衍射级次差i=4.附图8给出了所设计AWG的频谱图，其中最大信道波长漂移为0.025nm(小于信道间距1.6nm的二十分之一0.08nm)。为了能更好体现本发明的优越性，附图9给出了在3种(方法一、只采用带角度的耦合器设计;方法二、仅使用不同衍射级次设计；方法三、即为本发明所述的采用不同衍射级次和带角度耦合器设计)不同的偏振补偿方法下得到的各通道的偏振波长漂移情况，很显然，本发明所述的偏振补偿方法实现了AWG各信道波长的均匀偏振补偿。 Select the material SOI, in which the thickness of the Si core layer is 220nm, the thickness of the buried lower cladding layer _SiO2 is 1μm, and an 8×8AWG with a channel spacing of 1.6nm is designed. The index of uniform polarization compensation requires that the wavelength drift of each channel is less than that of the channel one-twentieth of the distance. Under the condition that the width of the core Si waveguide is 380nm (this width has a relatively good manufacturing tolerance), the accompanying drawing 7 shows the

In the case that the upper cladding is air, silicon dioxide and SU-8 polymer, the change with wavelength can be seen from the figure, choosing SU-8 as the upper cladding of the Si waveguide can get a smaller

value, so as to obtain a better polarization compensation effect. In addition, in the case of SU-8 as the upper cladding layer, the TM diffraction order is m = 16, and the diffraction order difference between the TE and TM modes is i = 4. Accompanying drawing 8 shows the spectrum diagram of the designed AWG, where The maximum channel wavelength shift is 0.025nm (0.08nm less than one-twentieth of the channel spacing of 1.6nm). In order to better reflect the superiority of the present invention, accompanying drawing 9 has provided in 3 kinds (method one, only adopt the coupler design with angle; Method two, only use different diffraction orders to design; Method three, be based on The polarization wavelength drift situation of each channel obtained under the different polarization compensation methods described in the invention using different diffraction orders and band angle coupler design, obviously, the polarization compensation method described in the present invention has realized the AWG each channel wavelength Uniform polarization compensation.

Note that the above-mentioned embodiments are used to illustrate the present invention, rather than to limit the present invention. Within the spirit of the present invention and the scope of protection of the claims, any amendments and changes made to the present invention will fall within the scope of the present invention. protected range.

Claims (5)

1. A method for realizing uniform polarization compensation of arrayed waveguide grating is characterized in that when light is transmitted to an output waveguide (5) from an input waveguide (1) sequentially through an input slab waveguide region (2), an arrayed waveguide region (3) and an output slab waveguide region (4), the total optical path difference corresponding to two adjacent waveguides in the arrayed waveguide region (3) is determined by the optical path difference in the input slab waveguide region (2), the arrayed waveguide region (3) and the output slab region (4); the method is characterized in that: birefringence differences exist between the two polarization state modes of the input slab waveguide area (2), the array waveguide area (3) and the output slab waveguide area (4); after two polarization states in the array waveguide region (3) use different diffraction orders, the remaining polarization wavelength drift is compensated by the input slab waveguide region (2) and the output slab waveguide region (4) together; the selection of the waveguide upper cladding material of the input slab waveguide region (2) and the output slab waveguide region (4) is determined by the waveguide material in the array waveguide region (3), the waveguide structure and the requirement on polarization dispersion compensation in design; the geometrical shapes of the input panel waveguide area (2), the output panel waveguide area (4) and the array waveguide area (3) are determined by waveguide materials in the array waveguide area (3), waveguide structures and requirements for polarization dispersion compensation in design, so that the requirements for uniform polarization dispersion compensation of the wavelength of each output channel of the array waveguide grating are met.

2. The method of claim 1, wherein the arrayed waveguide grating is configured to implement uniform polarization compensation, and the method further comprises: two polarization states in the array waveguide region (3), namely a transverse electric mode (TE) mode and a transverse magnetic mode (TM) mode, adopt the residual polarization wavelength drift after different diffraction orders and are jointly compensated by the input panel waveguide region (2) and the output panel waveguide region (4); namely: the difference in length in the input slab waveguide region (2) is∆L ₀The difference in length in the output slab waveguide region (4) is∆LThe difference in length in the arrayed waveguide region (3) is _a∆L，∆L ₀、∆LAnd _a∆Lthe relationship between the three is

And

wherein

Represents the effective refractive index of the transverse electric mode TE in the input slab waveguide region (2) and the output slab waveguide region (4) and varies with the wavelength,represents the effective refractive index of the transverse electric mode TE in the arrayed waveguide region (3) and varies with the wavelength,

shows the effective refractive index of the transverse magnetic mode TM in the input slab waveguide region (2) and the output slab waveguide region (4) and changes along with the wavelength,

represents the effective refractive index of a transverse magnetic mode (TM) in the arrayed waveguide region (3) and changes along with the wavelength;mis a diffraction order and is a positive integer greater than zero,ian integer representing the difference in diffraction orders between the transverse electric mode TE and the transverse magnetic mode TM and being non-zero.

3. The method of claim 1, wherein the arrayed waveguide grating is configured to implement uniform polarization compensation, and the method further comprises: the waveguide upper cladding materials of the input slab waveguide area (2) and the output slab waveguide area (4) are the same as or different from the waveguide upper cladding material of the array waveguide area (3), and the selection of the waveguide upper cladding material is completely determined by the waveguide material in the array waveguide area (3), the waveguide structure and the requirement on polarization dispersion compensation in design.

4. The method of claim 1, wherein the arrayed waveguide grating is configured to implement uniform polarization compensation, and the method further comprises: after the waveguide material, the waveguide structure and the requirement for polarization dispersion compensation in design in the array waveguide region (3) are determined, the geometric shapes of the input panel waveguide region (2), the output panel waveguide region (4) and the array waveguide region (3) are determined according to the central wavelength lambda in the designed wavelength range₀、mAndidetermining, i.e. from the relation

And (6) determining.

5. The method of claim 4, wherein the arrayed waveguide grating is configured to implement uniform polarization compensation, and the method further comprises: the included angle alpha between the tangent (6) of the boundary curve center of the input panel waveguide area and the array waveguide area and the optical axis (7) of the input panel waveguide area is a certain angle of more than 30 degrees and less than 90 degrees and more than 90 degrees and less than 150 degrees; the included angle alpha between the tangent line (11) at the center of the boundary curve of the output slab waveguide region and the array waveguide region and the optical axis (13) of the output slab waveguide region is at an angle of 30 DEG & lt alpha & lt 90 DEG and 90 DEG & lt alpha & lt 150 DEG, and is determined by the length difference of the input slab waveguide region (2)∆L ₀And the distance between the center of the middle arrayed waveguide in the arrayed waveguide region (3) and the central connecting line of the adjacent arrayed waveguides.

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