Polarization insensitive arrayed waveguide grating

Abstract

The present disclosure provides a polarization-insensitive array waveguide grating applied to the field of optical communication wavelength division multiplexing technology, comprising: an input channel waveguide, which inputs multi-wavelength mixed polarization state composite light into an input slab waveguide area; the input slab waveguide area diffracts the multi-wavelength mixed polarization state composite light; a first array waveguide module, which performs power distribution on the diffracted light from the input slab waveguide area to form a plurality of first composite lights, and transmits the first composite lights to corresponding polarization beam splitters respectively; a polarization beam splitter module, which separates each first composite light into a plurality of multi-wavelength second composite lights with single polarization; a second array waveguide module, which transmits the plurality of second composite lights to an output slab waveguide area respectively; the output slab waveguide area diffracts the plurality of second composite lights and focuses the diffracted light of different wavelengths to different output channel waveguides; and the output channel waveguide, which outputs light of different polarization states at the same specific wavelength.

Description

Technical Field

[0001] This disclosure relates to the field of optical communication wavelength division multiplexing technology, and in particular to a polarization-insensitive arrayed waveguide grating. Background Technology

[0002] With the rapid development of 5G, cloud computing, big data, and artificial intelligence technologies, the demand for high-speed, high-bandwidth optical communication in data centers continues to grow, driving the evolution of optical communication technology towards higher bandwidth and lower power consumption. Against this backdrop, wavelength division multiplexing (WDM), as one of the key technologies in optical communication, has become an important solution for coping with the explosive growth of data traffic because it can multiplex optical signals of multiple wavelengths into a single optical fiber, thereby significantly improving the transmission capacity of the fiber.

[0003] Arrayed waveguide gratings (ARGs) are core components in wavelength division multiplexing (WDM) systems, widely used for wavelength multiplexing and demultiplexing. ARGs separate or combine optical signals of different wavelengths using a set of arrayed waveguides, significantly improving the bandwidth utilization efficiency of WDM systems. However, due to the inherent polarization sensitivity of ARGs, their responses to optical signals with different polarization states are inconsistent, potentially leading to fluctuations in output signal power and affecting the performance and reliability of optical communication systems. Therefore, reducing or eliminating the polarization sensitivity of ARGs is an important research direction for improving the performance of optical communication systems.

[0004] Currently, a common solution is to use a polarization beam rotator to decompose and convert the mixed polarization state of light into a single polarization state (usually the TE mode), and then combine the beams before inputting them into an arrayed waveguide grating to achieve polarization-insensitive wavelength multiplexing and demultiplexing. Alternatively, some solutions achieve polarization-insensitive operation by inputting the two TE mode beams output from the polarization beam rotator into two separate arrayed waveguide gratings. However, these methods increase device design complexity and manufacturing costs due to the polarization state rotation and beam combining operations, and also introduce potential errors.

[0005] Therefore, effectively solving the polarization sensitivity problem when using arrayed waveguide gratings to achieve wave decomposition and multiplexing, and ensuring the performance and stability of optical communication systems, is a challenging task. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] The present invention provides a polarization-insensitive arrayed waveguide grating, which at least partially solves one of the above-mentioned technical problems.

[0008] (II) Technical Solution

[0009] The polarization-insensitive arrayed waveguide grating provided in this embodiment includes: an input channel waveguide for inputting received multi-wavelength mixed polarization state composite light into an input planar waveguide region; an input planar waveguide region for diffracting the received multi-wavelength mixed polarization state composite light; a first arrayed waveguide module for power distribution of the diffracted light received from the input planar waveguide region to form multiple first composite lights, and transmitting the multiple first composite lights to corresponding polarization beams; wherein the first composite light is multi-wavelength composite light with mixed polarization states; a polarization beamsplitter module for separating each first composite light into multiple second composite lights, wherein the second composite lights are multi-wavelength light with a single polarization state; a second arrayed waveguide module for transmitting the multiple second composite lights to an output planar waveguide region; an output planar waveguide region for diffracting the received multiple second composite lights, and focusing the diffracted light of different wavelengths onto different output channel waveguides; and an output channel waveguide, each specific output channel waveguide for outputting light of different polarization states at the same specific wavelength.

[0010] Optionally, the first array waveguide module includes multiple first array waveguides, and the polarization beamsplitter module includes multiple polarization beamsplitters. The number of polarization beamsplitters is the same as the number of first array waveguides, and each first array waveguide is connected to a corresponding polarization beamsplitter.

[0011] Optionally, when the multi-wavelength mixed polarization state composite light reaches the end face of the first array waveguide after being diffracted by the input planar waveguide region, the end face of the first array waveguide performs power distribution on the diffracted light to form multiple first composite lights and couple them into the corresponding first array waveguides.

[0012] Optionally, the second array waveguide module includes multiple second array waveguide groups, each second array waveguide group includes two second array waveguides, each second array waveguide group is connected to a polarization beam splitter, and each second array waveguide in the second array waveguide group is used to transmit a second composite light beam.

[0013] Optionally, the number of second array waveguide groups in the second array waveguide module is the same as the number of first array waveguides, and the number of second array waveguides in the second array waveguide module is twice the number of first array waveguides.

[0014] Optionally, the first array waveguides in the first array waveguide module are arranged at equal intervals, while the second array waveguides in the second array waveguide module are arranged at non-equal intervals.

[0015] Optionally, the spacing between the first array waveguides is determined by the minimum decoupling distance between adjacent array waveguides; the spacing between the second array waveguide groups is determined by the minimum decoupling distance; the array waveguides corresponding to the second composite light with the same polarization state in the second array waveguide module are arranged at equal intervals; and the ratio between the array waveguides corresponding to the second composite light with different polarization states is a constant.

[0016] Optionally, for the second composite light with the same polarization state, the length difference between the total lengths of the array waveguides corresponding to adjacent polarization beamsplitters is the same, wherein the total length of the array waveguide is the sum of the lengths of the first array waveguide corresponding to the polarization beamsplitter and the lengths of the second array waveguides in the polarization beamsplitter corresponding to the second composite light with the same polarization state; for the second composite light with different polarization states, the ratio of the difference in the total lengths of the array waveguides corresponding to different polarization states in adjacent polarization beamsplitters is a constant.

[0017] Optionally, in the output planar waveguide region, light of different polarization states at the same wavelength in the second composite light after diffraction is focused at the same output channel waveguide port, and polarization-insensitive wavelength demultiplexing is completed through transmission through the output channel waveguide.

[0018] Optionally, the input planar waveguide region and the output planar waveguide region satisfy the Rowland circle and grating circle structure, and the input channel waveguide is located at the center of the grating circle of the input planar waveguide region.

[0019] (III) Beneficial Effects

[0020] The polarization-insensitive arrayed waveguide grating provided in this disclosure has at least the following advantages:

[0021] (1) By adding a polarization beam splitter to the array waveguide of the array waveguide grating, the separation of different polarization states is achieved. By calculating the length difference between adjacent array waveguides with the same polarization state and the spacing between array waveguides with the same polarization state, the focusing of different polarization states under the same wavelength in the same output channel waveguide is achieved, thereby completing the polarization-insensitive wavelength demultiplexing.

[0022] (2) To achieve wavelength separation of multi-wavelength optical signals with mixed polarization states, effectively utilize the large bandwidth of optical fiber, and greatly improve the transmission rate of optical communication network.

[0023] (3) No polarization rotation device is required, and it has the characteristics of simple structure, low polarization correlation loss and excellent crosstalk. Attached Figure Description

[0024] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0025] Figure 1The schematic diagram illustrates a polarization-insensitive arrayed waveguide grating provided in an embodiment of the present disclosure;

[0026] Figure 2 This schematically illustrates the structural diagram between the input planar waveguide region and the first arrayed waveguide module of the polarization-insensitive arrayed waveguide grating provided in an embodiment of the present disclosure.

[0027] Figure 3 This schematic diagram illustrates the structure between the output planar waveguide region of the polarization-insensitive arrayed waveguide grating and the second arrayed waveguide module provided in an embodiment of this disclosure.

[0028] Figure 4 The schematic diagram illustrates the principle of focusing light of different polarization states at the same output channel waveguide position in the output planar waveguide region of the polarization-insensitive arrayed waveguide grating provided in the embodiments of this disclosure.

[0029] [Attached image labels]

[0030] 110 - Input channel waveguide; 120 - Input planar waveguide region; 130 - First array waveguide module; 140 - Polarization beam splitter module; 150 - Second array waveguide module; 151 - Second array waveguide for transmitting TE-polarized light; 152 - Second array waveguide for transmitting TM-polarized light; 160 - Output planar waveguide region; 170 - Output channel waveguide; 171 - Center output channel waveguide; 10 - TE-polarized light; 20 - TM-polarized light; 11 - Spacing of the first array waveguides ;12-Array waveguide spacing d for transmitting TE-polarized light TE ;13-Array waveguide spacing d for transmitting TM polarized light TM ;14- The spacing d between the array waveguide transmitting TM polarized light and the array waveguide transmitting TE polarized light TE-TM ;15 - Output channel waveguide spacing. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] In the description of this invention, it should be understood that the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the subsystem or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] Throughout the accompanying drawings, identical elements are represented by the same or similar reference numerals. Conventional structures or configurations may be omitted where they might cause confusion in understanding the invention. Furthermore, the shapes, sizes, and positional relationships of the components in the drawings do not reflect actual size, scale, or actual positional relationships. Additionally, any reference numerals placed between parentheses in the claims should not be construed as limiting the claims.

[0036] Similarly, to simplify the invention and aid in understanding one or more of the various disclosed aspects, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together into a single embodiment, figure, or description thereof. The use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] Figure 1 A schematic diagram of a polarization-insensitive arrayed waveguide grating provided according to an embodiment of the present disclosure is shown.

[0039] like Figure 1 As shown, the polarization-insensitive arrayed waveguide grating provided in this embodiment includes: an input channel waveguide 110, an input planar waveguide region 120, a first arrayed waveguide module 130, a polarization beam splitter module 140, a second arrayed waveguide module 150, an output planar waveguide region 160, and an output channel waveguide 170.

[0040] The input channel waveguide 110 is used to input the received multi-wavelength mixed polarization state composite light into the input planar waveguide region. The multi-wavelength mixed polarization state composite light can be, for example, a multi-wavelength transverse electric (TE) and transverse magnetic (TM) mixed polarization state composite light.

[0041] In some embodiments, both the input planar waveguide region and the output planar waveguide region satisfy the traditional Rowland circle and grating circle structure, and the input channel waveguide is a central input channel waveguide, which is located at the center of the grating circle in the input planar waveguide region.

[0042] The input planar waveguide region 120 is used to diffract the received multi-wavelength mixed polarization state composite light.

[0043] The first array waveguide module 130 is used to perform power distribution on the diffracted light received from the input planar waveguide region 120 to form multiple first composite lights, and transmit the multiple first composite lights to the corresponding polarization beam splitters respectively.

[0044] In some embodiments, the first array waveguide module includes multiple first array waveguides arranged at equal intervals. Multi-wavelength mixed polarization composite light is diffracted by the input planar waveguide region and reaches the end face of the first array waveguide. The end face of the first array waveguide performs power distribution on the diffracted light to form multiple first composite lights, which are then coupled into the corresponding first array waveguides, ensuring that each array waveguide receives appropriate optical power.

[0045] The polarization beam splitter module 140 is used to separate each first composite light into multiple second composite lights, wherein the second composite lights are multi-wavelength lights with a single polarization.

[0046] In some embodiments, the polarization beamsplitter module includes multiple polarization beamsplitters, the number of which is the same as the number of the first array waveguides. Each polarization beamsplitter is connected to a corresponding first array waveguide and is used to split the first composite light transmitted through the first array waveguide, separating the first composite light with mixed polarization state into multiple beams of multi-wavelength composite light with single polarization state (i.e., second composite light). The second composite light may, for example, include second composite light with TE polarization state and second composite light with TM polarization state.

[0047] The second array waveguide module 150 is used to transmit multiple beams of second composite light to the output planar waveguide region respectively.

[0048] In some embodiments, the second array waveguide module includes multiple second array waveguide groups, each second array waveguide group including two second array waveguides. The number of second array waveguide groups is the same as the number of first array waveguides, and the number of second array waveguides in the second array waveguide module is twice the number of first array waveguides. The second array waveguides in the second array waveguide module are arranged non-equidistantly. Each second array waveguide group is correspondingly connected to a polarization beam splitter, and each second array waveguide in the second array waveguide group is used to transmit a second composite light beam.

[0049] For example, when the multi-wavelength mixed polarization state composite light input to the polarization-insensitive arrayed waveguide grating is a multi-wavelength TE / TM mixed polarization state composite light, one second arrayed waveguide is used to transmit the second composite light with TE polarization state (hereinafter referred to as the TE second arrayed waveguide), and another arrayed waveguide is used to transmit the second composite light with TM polarization state (hereinafter referred to as the TM second arrayed waveguide). The first composite light is separated by a polarization beam splitter to obtain the second composite light with TE polarization state and the second composite light with TM polarization state. The second composite light with TE polarization state and the second composite light with TM polarization state are respectively transmitted into the corresponding second arrayed waveguides, and then transmitted by the second arrayed waveguides to the output planar waveguide region.

[0050] The spacing between the TE second array waveguide and the TM second array waveguide is determined by the minimum decoupling distance, and the ratio of the spacing between each TE second array waveguide to the spacing between each TM second array waveguide is a constant (i.e., ...). Figure 3 (The ratio between 12 and 13 is constant). In the second array waveguide module, the array waveguides with the same single polarization state are equally spaced. The total length difference between the array waveguides corresponding to adjacent polarization beamsplitters is the same, where the total array waveguide length is the sum of the lengths of the first array waveguide corresponding to that polarization beamsplitter and the second array waveguide corresponding to the second composite light with that polarization state in that polarization beamsplitter. The ratio of the difference in the total length of the array waveguides corresponding to different polarization states in adjacent polarization beamsplitters is constant.

[0051] For example, polarization beamsplitter A is connected to the first array waveguide 131A, and polarization beamsplitter A is also connected to the second array waveguide 151A and the second array waveguide 152A (assuming the second array waveguide 151A is used to transmit the second composite light with TE polarization, and the second array waveguide 152A is used to transmit the second composite light with TM polarization). Then, for the second composite light with TE polarization, the total length of the array waveguides corresponding to polarization beamsplitter A can be, for example, the length L of the first array waveguide 131A. 131A The length L of the second array waveguide 151A 151A The sum of these values ​​represents the total length L of the array waveguide corresponding to polarization beam splitter A. A =L 131A +L 151A Polarizing beamsplitter B and polarizing beamsplitter A are adjacent beamsplitters. Polarizing beamsplitter B is connected to the first array waveguide 131B, and also to the second array waveguide 151B and the second array waveguide 152B (assuming the second array waveguide 151B is used to transmit the second composite light with TE polarization, and the second array waveguide 152B is used to transmit the second composite light with TM polarization). Therefore, for the second composite light with TE polarization, the total length of the array waveguides corresponding to polarizing beamsplitter B can, for example, be the length L of the first array waveguide 131B. 131B The length L of the second array waveguide 151B 151B The sum, i.e., the total length L of the array waveguide corresponding to polarization beam splitter B. B =L 131B +L 151B Then the length difference between the total lengths of the array waveguides corresponding to polarization beamsplitter A and polarization beamsplitter B is L. B -L A For the second composite light in the TM polarization state, the total waveguide length corresponding to its polarization beamsplitter is similarly represented, that is, for the second composite light in the TM polarization state, the total array waveguide length L corresponding to polarization beamsplitter A is... A =L 131A +L 152A The total length L of the array waveguide corresponding to polarization beam splitter B B =L 131B +L 152B .

[0052] The output planar waveguide region 160 is connected to the second array waveguide module and is used to diffract the received multiple beams of second composite light and focus the diffracted light of different wavelengths onto different output channel waveguides.

[0053] The output channel waveguide 170 is connected to the output planar waveguide region. Each specific output channel waveguide is used to output light with different polarization states at the same specific wavelength.

[0054] The specific process of wavelength demultiplexing based on the polarization-insensitive arrayed waveguide grating provided in this embodiment is as follows: Multi-wavelength TE and TM mixed polarization state composite light enters the input planar waveguide region 120 of the polarization-insensitive arrayed waveguide grating through the input channel waveguide 110, and diffracts in this region. The diffracted light is power-distributed on the end face of the first arrayed waveguide module 130 and coupled into the first arrayed waveguide. After a section of transmission through the first arrayed waveguide, the light reaches the polarization beamsplitter 140. The polarization beamsplitter 140 separates the mixed polarization state multi-wavelength composite light into two beams of multi-wavelength composite light (i.e., the second composite light) each having a single polarization state 10-20 (TE or TM). Subsequently, these two beams of light with a single polarization state (i.e., the second composite light) are guided to their corresponding second arrayed waveguides 151 and 152, respectively, and transmitted to the output planar waveguide region 160 via the second arrayed waveguides. In the output planar waveguide region 160, the light is diffracted and interfered again. Through the focusing of the output planar waveguide region 160 and the output of the output channel waveguide 170, the polarization-insensitive wavelength demultiplexing is finally completed.

[0055] For a composite light with mixed polarization states 10-20 of TE and TM at a center wavelength of λ0, when it is input into a polarization-insensitive arrayed waveguide grating from the input channel waveguide 110 and output from the center output channel waveguide 171, the grating equation satisfied by the light with polarization state 10 of TE is:

[0056] The grating equation satisfied by light of polarization state 20 in TM is:

[0057]

[0058] in, and The effective refractive indices ΔL of light 10 in TE polarization state and light 20 in TM polarization state in the arrayed waveguide are respectively. TE ΔL is the difference in total array waveguide length corresponding to the TE polarization state of light 10 in adjacent polarization beams. TM The ratio is the difference in the total array waveguide lengths corresponding to the TM polarization state of light 20 in adjacent polarization beamsplitters. λ is a constant, m is the diffraction order, and λ0 is the center wavelength.

[0059] After the ratio of the length difference between the TE second array waveguide and the TM second array waveguide satisfies the above ratio relationship, the center wavelength of the TE polarization state is: The center wavelengths of the light 10 and TM polarization states are The light 20 will be simultaneously output from the central output channel waveguide 161.

[0060] Figure 2The schematic diagram illustrates the structure between the input planar waveguide region and the first arrayed waveguide module of the polarization-insensitive arrayed waveguide grating provided in the embodiments of this disclosure.

[0061] like Figure 2 As shown, the input channel waveguide 110 is located at the center of the grating circle, that is, this input channel waveguide is the central input channel waveguide 110, and the radius of the grating circle is R. in In the first array waveguide module 130 connected to the input planar waveguide region 120, multiple first array waveguides are evenly and uniformly arranged on the grating circle, with a spacing 11 between adjacent first array waveguides. in The spacing is determined by the minimum decoupling distance between adjacent waveguides, and the number of the first array waveguides connected to the input planar waveguide region 120 is N.

[0062] Figure 3 The schematic diagram illustrates the structure between the output planar waveguide region of the polarization-insensitive arrayed waveguide grating and the second arrayed waveguide module provided in the embodiments of this disclosure.

[0063] Figure 4 The schematic diagram illustrates the principle of focusing light of different polarization states at the same output channel waveguide position in the output planar waveguide region of the polarization-insensitive arrayed waveguide grating provided in the embodiments of this disclosure.

[0064] like Figure 3 , Figure 4 As shown, for the multi-wavelength composite light 10-20 with mixed polarization states of TE and TM, the role dispersion equations satisfied by the output channel waveguide 160 of the arrayed waveguide grating are as follows:

[0065]

[0066]

[0067] in, The angle of departure. For wavelength, and The effective refractive indices of light with polarization states TE and TM, 10-20, in the planar waveguide region, 120-150, respectively. Let be the group refractive index of light 10 in the TE polarization state in the TE array waveguide (i.e., the first array waveguide or the second TE array waveguide used to transmit the TE polarization state composite light). Let d be the group refractive index of the TM-polarized light 20 in the TM array waveguide (i.e., the first array waveguide or the second TM array waveguide used to transmit the TM-polarized composite light). TE The spacing 12, d is the distance between the adjacent second array waveguides (i.e., the second array waveguides of TE) corresponding to polarization state 10 of TE. TMThe spacing 13 is the distance between the adjacent second array waveguide (i.e., the second array waveguide of TM) corresponding to the TM polarization state 20.

[0068] The multi-wavelength composite light 10-20 in TE polarization state and TM polarization state can only be focused at the same output channel waveguide 170 position under the condition that the polarization-insensitive wavelength demultiplexing equation is equal, thus achieving polarization-insensitive wavelength demultiplexing. Therefore, the relationship between the TE polarization state light 10 and the TM polarization state light 20 connected to the output planar waveguide 160, corresponding to the TE second array waveguide spacing 12 and the TM polarization state light 20, corresponding to the TM second array waveguide spacing 13, is as follows:

[0069]

[0070] It can be seen from this formula that d TE and d TM The ratio between them is constant. The spacing 14 between the TE second array waveguide and the TM second array waveguide can be expressed as d. TE-TM d TE-TM It is determined by the minimum decoupling distance between adjacent waveguides.

[0071] In d TE and d TM Under certain ratio conditions, the role dispersion equations of multi-wavelength composite light with TE polarization state and TM polarization state are equal. That is, for light with TE (or TM) polarization state, the equally spaced wavelengths will be arranged at equal intervals on the circumference of the Rowland circle at the output end.

[0072] See Figure 1 , Figure 3 After being split by polarization beam splitter 140, the light is divided into multi-wavelength composite light (i.e., second composite light) with TE polarization state 10 and TM polarization state 20, and then input into the corresponding second array waveguide 151 and second array waveguide 152 respectively. The number of first array waveguides is N, and the number of second array waveguides is 2N.

[0073] The angular spacing of adjacent output channel waveguides 170 can be expressed as:

[0074]

[0075] Where Δλ is the wavelength spacing of the output waveguides, light with TE and TM mixed polarization states input from the central input channel waveguide 110 at equal intervals of wavelength Δλ will be output from the equally spaced output channel waveguides 170. Based on the geometric relationship of the grating circle satisfied by the output planar waveguide region 160, we can obtain:

[0076]

[0077] in The output channel waveguide spacing is 15, Rout The radius of the 160 grating circle in the output planar waveguide region:

[0078]

[0079] See Figure 2 , 3 Since the light is input from the central input channel waveguide 110, the radius R of the grating circle in the input planar waveguide region 120 is... in It will not affect the expression of the grating equation. Therefore, R in With R ou It can be set to equal or unequal values; the specific parameters need to be selected according to the actual layout.

[0080] See Figure 4 In the output planar waveguide region 160, the light of different polarization states at the same wavelength in the second composite light after diffraction (e.g., the light of TE polarization state 10 and TM polarization state 20 at the same wavelength) is focused at the same output channel waveguide 170 port, and polarization-insensitive wavelength demultiplexing is completed through the transmission of the output channel waveguide 170.

[0081] As an optional embodiment, the material of the above-mentioned polarization-insensitive array waveguide grating is silicon nitride to meet the optoelectronic performance requirements of the semiconductor device.

[0082] Optionally, the thickness of the silicon nitride polarization-insensitive arrayed waveguide grating is 400 nm, and the waveguide width is chosen to be 800 nm to meet single-mode transmission in the O-band. Under this condition... , , , , , Optionally, the silicon nitride polarization-insensitive arrayed waveguide grating meets the application requirements of coarse wavelength division multiplexing in the O-band, so the output four channel wavelengths are 1271nm, 1291nm, 1311nm, and 1331nm, respectively.

[0083] The main conditions satisfied by the silicon nitride polarization-insensitive waveguide grating designed with the above parameters are as follows: the spacing between the first array waveguides in the first array waveguide module... The first array waveguide number is N=29, and the length difference of the array waveguides corresponding to the TE polarized light is... The length difference of the array waveguide corresponding to the TM polarized light The minimum decoupling distance between adjacent waveguides is determined as follows: TE / TM two-polarization state array waveguide spacing

[0084] Therefore, the spacing of the array waveguides corresponding to the TE / TM polarization states connected to the output planar waveguide region can be set as... , Output channel waveguide spacing The number of array waveguides connected to the output planar waveguide is N=58.

[0085] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A polarization-insensitive arrayed waveguide grating, characterized in that, The polarization-insensitive arrayed waveguide grating comprises: an input channel waveguide for inputting received multi-wavelength mixed polarization state composite light to an input slab waveguide region; an input slab waveguide region for diffracting the received multi-wavelength mixed polarization state composite light; a first array waveguide module for power dividing the received diffracted light from the input slab waveguide region to form a plurality of first composite lights and transmitting the plurality of first composite lights to corresponding polarization beam splitters respectively; wherein the first composite light is multi-wavelength composite light mixed with multiple polarization states; the first array waveguide module comprises a plurality of first array waveguides, and the spacing between the first array waveguides is determined by the decoupling distance of adjacent array waveguides; a polarization beam splitter module for separating each first composite light into a plurality of second composite lights, wherein the second composite light is multi-wavelength light with a single polarization; a second array waveguide module for transmitting a plurality of second composite lights to an output slab waveguide region respectively; an output slab waveguide region for diffracting the received plurality of second composite lights and focusing diffracted light of different wavelengths to different output channel waveguides respectively; an output channel waveguide, each specific output channel waveguide being used for outputting light of different polarization states at the same specific wavelength; wherein the second array waveguide module comprises a plurality of second array waveguide groups, each second array waveguide group comprising two second array waveguides, each second array waveguide group being connected to a polarization beam splitter correspondingly, and each second array waveguide in the second array waveguide group being used for transmitting second composite light of different polarization states to the output slab waveguide region respectively; the spacing between the second array waveguides is determined by the minimum decoupling distance, and the spacing between the array waveguides corresponding to the second composite light of the same polarization state in the second array waveguide module is equally arranged, and the ratio between the spacing between the array waveguides corresponding to the second composite light of different polarization states is a constant.

2. The polarization-insensitive arrayed waveguide grating according to claim 1, wherein, The polarization beam splitter module comprises a plurality of polarization beam splitters, and the number of polarization beam splitters is the same as the number of first array waveguides, and each first array waveguide is connected to a polarization beam splitter correspondingly. 3.The polarization-insensitive arrayed waveguide grating according to claim 1, wherein, After the multi-wavelength mixed polarization state composite light is diffracted by the input slab waveguide region and reaches the end face of the first array waveguide, the diffracted light is power divided by the first array waveguide end face to form a plurality of first composite lights and coupled into the corresponding first array waveguide.

4. The polarization-insensitive arrayed waveguide grating according to claim 2, wherein, The number of second array waveguide groups in the second array waveguide module is the same as the number of first array waveguides, and the number of second array waveguides in the second array waveguide module is twice the number of first array waveguides.

5. The polarization-insensitive arrayed waveguide grating according to claim 1, wherein, The first array waveguides in the first array waveguide module are equally arranged, and the second array waveguides in the second array waveguide module are not equally arranged. 6.The polarization-insensitive arrayed waveguide grating according to claim 1, wherein, For the second composite light of the same polarization state, the length difference between the total lengths of the array waveguides corresponding to adjacent polarization beam splitters is the same, wherein the total length of the array waveguide is the sum of the length of the first array waveguide corresponding to the polarization beam splitter and the length of the second array waveguide corresponding to the polarization beam splitter and the second composite light of the same polarization state. The ratio of the difference between the total lengths of the array waveguides corresponding to different polarization states in adjacent polarization beam splitters is a constant for the second composite light of different polarization states. 7.The polarization-insensitive arrayed waveguide grating according to claim 1, wherein, In the output slab waveguide region, the light of different polarization states at the same wavelength in the diffracted second composite light is focused on the same output channel waveguide port, and the polarization-insensitive wavelength demultiplexing is completed through the transmission of the output channel waveguide. 8.The polarization-insensitive arrayed waveguide grating according to claim 1, wherein, The input slab waveguide region and the output slab waveguide region satisfy the Rowland circle and the grating circle structure, and the input channel waveguide is arranged at the center position of the grating circle of the input slab waveguide region.

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