N*N optical switch architecture, design method and N*N optical switch array

Abstract

The invention discloses an N * N optical switch architecture, a design method and an N * N optical switch array. The N * N optical switch architecture comprises N input waveguides, a multimode waveguide, N output waveguides and a plurality of strip-shaped electrodes located in a multimode waveguide area, in the waveguide plane, the N input waveguides and the N output waveguides are arranged at equal intervals in the direction perpendicular to light beam transmission, and each input port and the output port at the corresponding position form a pair of input-output port combinations. The plurality of strip-shaped electrodes are arranged in a multimode waveguide area in an (N + 1) * M array, the N + 1 strip-shaped electrodes in each column form a single-stage strip-shaped electrode array, and the N + 1 strip-shaped electrodes in each column are symmetrically arranged by taking a center connecting line of N pairs of input-output port combinations as a symmetric center; m represents the number of cascading times of the optical switch, and # imgabs0. The optical switch has the advantages of being simple in circuit driving, insensitive in polarization and wide in wavelength application range, and an N * N large-port optical switch can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of optical communications, and in particular to an N×N optical switch architecture, a design method and an N×N optical switch array. Background Art

[0002] Optical switches are important components in the field of optical communication technology, used to flexibly and quickly switch optical signal paths to achieve information exchange functions. Flexible, fast, large-port performance and excellent non-blocking N×N optical switches can increase network bandwidth and capacity, support more data channels, reduce latency, meet dynamic routing requirements, and enhance network flexibility and scalability.

[0003] In the related technology, the commonly used N×N optical switch solution is the Micro ElectroMechanical Systems (MEMS) optical switch. MEMS optical switches realize the reflection and switching of optical signals through the movement of micro-mechanical lenses. They usually support hundreds of ports and are suitable for large-scale network applications. Its advantages are low insertion loss and a wide range of applicable wavelengths. It is an existing mature commercial optical switch solution. However, the disadvantages of MEMS optical switches are that their mechanical structure is relatively complex, the switching speed is relatively slow, and there are potential problems with reliability and life in long-term use.

[0004] Integrated optical switches are another solution that has the advantages of small size, low power consumption, and suitability for mass production, and are suitable for high-speed and high-capacity optical communication networks. Common integrated optical switches include MicroRing Resonators (MRRs) and Mach-Zehnder Interferometers (MZIs). MRR optical switches use the resonance characteristics of microrings to control light of specific wavelengths, and have the advantages of small size, low power consumption, and high wavelength selectivity. Its main disadvantage is that its bandwidth is narrow, which limits it to work only within a specific wavelength range. It is also extremely sensitive to temperature changes, which can easily cause the resonant wavelength to drift. This limits its performance in broadband applications and scenarios that require high stability.

[0005] MZI optical switches realize the switching of optical paths based on the principle of interference. They have a simple structure and are suitable for large-scale integration. They are widely used to realize N×N integrated optical switches. In the MZI cascade topology, the Benes-type structure is the first choice with a relatively small number of switch units. However, each optical switch unit in the Benes-type structure needs to process two optical signals at the same time, which easily generates high crosstalk. In addition, in the MZI optical switch unit, it is difficult for the phase adjustment arm to simultaneously meet the phase matching requirements of different wavelengths, which limits its application in multi-port multi-wavelength input scenarios. Path-Independent Insertion-Loss (PILOSS) and Switch and Select (S&S) are two strictly non-blocking optical switch topologies. Their characteristics are that each optical switch unit only allows a single optical signal to pass through at the same time, thereby avoiding the crosstalk problem in a single MZI optical switch unit in principle and realizing the path switching of multi-wavelength signals. However, their main problem is the large number of unit devices (~N 2 ), large port expansion is difficult, and there is a lot of optical path crosstalk, which affects the overall performance.

[0006] In summary, integrated optical switches represented by MZI and MRR types are based on the principle of single-mode phase interference, and the number of ports of their unit devices is limited to 1×1 and 2×2. As the number of ports increases, a large number of cascaded unit devices are required, which makes the overall design complex, the driving difficulty increases, the manufacturing cost increases, and the single-mode waveguides in the transmission network need to cross multiple times, further reducing the device performance. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention provides an N×N optical switch architecture, design method and N×N optical switch array. By driving multiple strip electrodes in the optical switch, multiple optical signals with the same / different polarizations and the same / different wavelengths can be switched simultaneously to realize the N×N non-blocking optical switch function. The optical switch is easy to drive, has a short preparation cycle, low cost and a wide wavelength application range.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] An N×N optical switch architecture includes N input waveguides, a multimode waveguide and N output waveguides, and a plurality of strip electrodes located in the multimode waveguide region;

[0010] The input end of the input waveguide is connected to the input optical fiber array, the output end of the input waveguide is connected to the input end of the multimode waveguide; the output end of the multimode waveguide is connected to the input end of the output waveguide; the output end of the output waveguide is connected to the output optical fiber array; the input waveguide, the multimode waveguide and the output waveguide are all made of materials with thermo-optical effect;

[0011] In the waveguide plane, the direction of light beam transmission is defined as the x direction, and the direction perpendicular to the x direction is the y direction. N input waveguides and N output waveguides are arranged at equal intervals along the y direction, and each input port and the output port corresponding to the x direction form a pair of input-output port combinations;

[0012] The plurality of strip electrodes are arranged in an array of (N+1)×M in the multimode waveguide region, the N+1 strip electrodes in each column form a single-stage strip electrode array, and the N+1 strip electrodes in each column are symmetrically arranged with the center line of the N pairs of input-output port combinations as the symmetry center; M represents the number of cascades of the optical switch,

[0013] A thermo-optical waveguide lens or a thermo-optical waveguide lens group is constructed through the thermo-optical effect of the strip electrodes to regulate the light field propagation path and realize the optical signal switching function.

[0014] Furthermore, the N×N optical switch architecture further includes a first cladding, a first core layer and a second cladding; the first core layer is located between the first cladding and the second cladding, and the input waveguide, the multimode waveguide and the output waveguide are all located in the core layer.

[0015] Furthermore, the refractive index of the first core layer is greater than the refractive index of the first cladding layer and the second cladding layer.

[0016] Furthermore, the input waveguide includes a single-mode straight waveguide, a wedge-shaped waveguide and a single-mode bent waveguide.

[0017] Furthermore, the output waveguide includes a single-mode straight waveguide, a wedge-shaped waveguide and a single-mode bent waveguide.

[0018] A method for designing an N×N optical switch architecture as claimed in claim 1, comprising the following steps:

[0019] Step 1: Calculate the target path combination O required by the N×N optical switch ports tar , the number is N! ;

[0020] Step 2: Arrange N input ports and N output ports at equal intervals, and arrange the first-level strip electrode array according to the positions of the input ports and the output ports, and calculate all lens group combinations T and the number of combinations of the first-level strip electrode array;

[0021] Step 3: Determine all combinations T of the current strip electrode array and the target path combination O tar Are they the same? If T=O tar , then the arrangement of the strip electrode array is completed, and step five is executed; otherwise, a strip electrode array is added on the basis of the current condition electrode array, and step four is executed;

[0022] Step 4: Substitute all output path combinations of the previous strip electrode array into the input of the newly added strip electrode array, update all combinations T of the current strip electrode array, and return to step 3;

[0023] Step 5: Generate a mapping table of driving strip electrode configuration and output optical switch function.

[0024] An N×N optical switch array, wherein the N×N optical switch array is implemented based on an N×N optical switch architecture;

[0025] The multimode waveguide is a three-dimensional multimode waveguide;

[0026] Along the z direction which is perpendicular to both the x direction and the y direction, there are P layers of (N+1)×M strip electrode arrays and P layers of N pairs of input and output port combinations, and each layer of strip electrode arrays and N pairs of input and output port combinations are the same as the arrangement in the N×N optical switch architecture described in claim 1.

[0027] The beneficial effects of the present invention are as follows:

[0028] The optical switch of the present invention can realize a thermal optical waveguide lens (group) by setting a plurality of strip electrodes in the multimode waveguide region to switch the path of the optical signal and realize the N×N optical switch function, which can effectively solve the problems of complex driving, high loss, polarization sensitivity and narrow wavelength application range of the existing integrated optical switch, and avoid the single-mode waveguide cross structure. The optical switch of the present invention is simple to drive, short in preparation cycle, low in cost, and wide in wavelength application range, and can realize a low-cost, high-performance N×N large-port optical switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention.

[0030] Figure 1 It is a schematic diagram of the structure of an N×N optical switch provided for an embodiment of the present application.

[0031] Figure 2 yes Figure 1 The schematic diagram of the structure of the N×N optical switch along the cross section of the y direction and the z direction is shown.

[0032] Figure 3 This is a diagram of the simulation results of the electrode heating temperature gradient distribution provided for an embodiment of the present application.

[0033] Figure 4 yes Figure 3 , the parabolic distribution of the refractive index in the y direction of the central cross section of the multimode waveguide (at z = 0);

[0034] Figure 5 This is a diagram of a single-stage single-lens imaging simulation result of an N×N (1 to 4 input ports) optical switch provided in an embodiment of the present application.

[0035] Figure 6 This is a schematic diagram of an N×N single-stage optical switch structure provided for an embodiment of the present application;

[0036] Figure 7 This is a schematic diagram of an N×N multi-lens group M-stage cascade optical switch structure provided in an embodiment of the present application;

[0037] Figure 8 This is a schematic diagram of all achievable output combinations of a 3×3 optical switch provided in an embodiment of the present application;

[0038] Fig. 9 This is a schematic diagram of an achievable output combination of a first stage of a 3×3 optical switch provided in an embodiment of the present application;

[0039] Fig.10 This is a schematic diagram of an achievable output combination of the second stage of a 3×3 optical switch provided in an embodiment of the present application;

[0040] Fig.11 This is a simulation result diagram of all six possible output combinations of a 3×3 optical switch provided in an embodiment of the present application;

[0041] Fig.12 This is a chip measurement end face imaging result diagram of all 6 possible output combinations of a 3×3 optical switch provided in an embodiment of the present application;

[0042] Fig.13 This is a calculation result diagram of the number of output combinations that can be realized at each stage of an N×N optical switch provided in an embodiment of the present application; DETAILED DESCRIPTION

[0043] The present invention will be described in detail below based on the accompanying drawings and preferred embodiments, and the purpose and effects of the present invention will become more clear. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] Figure 1 This is a schematic diagram of the N×N optical switch structure provided by the example of this application. In the waveguide plane, the direction of light beam transmission is defined as the x direction, the direction perpendicular to the x direction is the y direction, and the direction perpendicular to the waveguide plane is the z direction. Figure 2 yes Figure 1 The schematic diagram of the structure of the N×N optical switch along the cross section of the y direction and the z direction is shown.

[0045] refer to Figure 1, the N×N optical switch includes N input waveguides 10, a multimode waveguide 20 and N output waveguides 30, as well as a strip electrode 40 in the multimode waveguide area. The input waveguide 10, the multimode waveguide 20 and the output waveguide 30 are arranged along the direction x, and the input end of the input waveguide 10 is connected to the input optical fiber array, and the output end thereof is connected to the input end of the multimode waveguide 20; the output end of the multimode waveguide 20 is connected to the input end of the output waveguide 30; the output end of the output waveguide 30 is connected to the output optical fiber array; the input waveguide 10, the multimode waveguide 20 and the output waveguide 30 are all made of optical waveguide materials with thermo-optical effects, such as polymers, silica, etc. In this embodiment, the input waveguide 10 and the output waveguide 30 are used to connect the multimode waveguide with the optical fiber array, to reduce the coupling loss between the device and the optical fiber array, and to reduce the crosstalk between different ports. The input waveguide and the output waveguide are both composed of a single-mode straight waveguide, a wedge-shaped waveguide and a single-mode curved waveguide. It is understandable that the input waveguide 10 and the output waveguide 30 can be designed into various geometric structures according to specific applications and functional requirements.

[0046] Multiple strip electrodes are located in the multimode waveguide area, and a Thermo-Optic Waveguide Lens (TOWL) and its combination are constructed through the thermo-optic effect to control the light field propagation path and realize the optical signal switching function. N input waveguides and N output waveguides are arranged at equal intervals along the y direction, and each input port and the output port at the corresponding position in the x direction form a pair of input-output port combinations; multiple strip electrodes are arranged in an array of (N+1)×M in the multimode waveguide area, and the N+1 strip electrodes in each column form a single-stage strip electrode array, and the N+1 strip electrodes in each column are symmetrically arranged with the center line of the N pairs of input-output port combinations as the symmetry center; M represents the number of cascades of the optical switch,

[0047] The optical switch can be driven by a single-stage strip electrode or a multi-stage cascade strip electrode. The number and length of the strip electrodes in each stage along the direction x can be the same or different.

[0048] refer to Figure 2 The waveguide chip includes a first cladding layer 50, a first core layer 60, a second cladding layer 70 and a silicon-based substrate 80 arranged in sequence along the direction z. Among them, the input waveguide 10, the multimode waveguide 20 and the output waveguide 30 are all located in the first core layer 60. The strip electrode 40 can be located above the first cladding layer 50, in the first cladding layer 50, in the first core layer 60, in the second cladding layer 70 or below the second cladding layer 70. In the direction z, electrodes located in the same xy plane are called a layer.

[0049] When the multimode waveguide is a three-dimensional multimode waveguide, along the z direction which is perpendicular to both the x direction and the y direction, there are P layers of (N+1)×M strip electrode arrays and P layers of N pairs of input and output port combinations. The strip electrode arrays and N pairs of input and output port combinations of each layer are arranged the same as those in a single-layer N×N optical switch architecture, thereby forming an N×N optical switch array.

[0050] The following will combine the principle of thermal optical waveguide lens and take two-dimensional multimode waveguide as an example to explain the optical switch function that can be realized in a single stage. Figure 3 ,When a pair of electrodes is heated, a temperature gradient distribution will be generated. Due to the thermo-optical effect, the refractive index in the multimode waveguide will be changed and present a parabolic distribution in the y direction, such as Figure 4 This parabolic refractive index distribution is similar to that of graded-index optical fibers and lenses, and can image the input light field in a 1:1 manner, and is called a thermal optical waveguide lens.

[0051] Figure 5 The simulation results of light field propagation of a single waveguide lens imaging with 1 to 4 input ports are shown. For the convenience of explanation, the input ports are represented by I1, I2, I3, etc., and the output ports are represented by O1, O2, O3, etc. In the first direction x, the shortest distance from the input to the image is called the period. It can be understood that if the number of periods is odd, the waveguide lens imaging is an inverted equal-sized real image (such as Figure 5 As shown in the figure, the symmetrical exchange distribution of the input port light field is realized (for example, in the three input ports, I1→O3, I2→O2, I3→O1). If it is an even number of periods, the waveguide lens images a real image of upright and equal size, which reproduces the distribution of the input port light field (for example, in the three input ports, I1→O1, I2→O2, I3→O3), that is, the light field propagation path remains unchanged. It can be understood that the optical path switching, that is, the optical switch function, can be realized through the above transformation.

[0052] It should be noted that the optical signals at the input ports can be of the same wavelength or different wavelengths, and can be of the same polarization or different polarizations. It is understandable that when at least one parameter in wavelength and polarization is different, the optical signals are orthogonal. Since the thermal optical waveguide lens is a device in which polarization and wavelength are unrelated, the exchange between optical signals with different polarizations and wavelengths can be achieved through the same strip electrode configuration. When the optical signals input from different ports have the same wavelength and polarization state, since multi-mode interference reflects the distribution of the light field in space, these optical signals undergo multi-mode interference in space and constructively interfere (constructive interference) at different spatial positions, thereby realizing the optical path switching function. Figure 5 This is the case shown in .

[0053] refer to Figure 6 It can be understood that multiple electrodes (2 or more) can be arranged in a single stage, and a pair of strip electrodes can realize a waveguide lens, thereby realizing a lens group "arranged in parallel" in the direction y. By switching different electrodes and changing the heating power, different combinations of lens groups can be realized to achieve different optical switch routing functions. Therefore, the optical switch combination that can be realized in a single stage is related to the number of waveguide lenses constructed when heating the strip electrodes. Input port I N Output port O N They are arranged one by one along the direction y and at equal intervals. Among them, each pair of input-output port combinations corresponds to a pair of electrodes, that is, this pair of electrodes is symmetrical about the current input-output port combination in the y direction. Since adjacent input-output port combinations can share one electrode (all white hollow electrodes), the shared electrode is located on the center line of adjacent input-output port combinations in the y direction. Therefore, the minimum number of electrodes required for a single-stage single-layer N×N optical switch is N+1. Among them, the minimum number of waveguide lenses in a single stage is theoretically 1, that is, single lens imaging. At this time, only one pair of electrodes needs to be heated (gray solid electrodes, E1 and E N+1 ). Relatively speaking, the maximum number of waveguide lenses in theory is N, that is, each port corresponds to a waveguide lens, and the number of electrodes required is N+1 (all gray solid electrodes and white hollow electrodes, where the electrodes between adjacent lenses are considered to be shared). At this time, the adjacent electrode pairs are related to the current I N / O N The ports are symmetrical in the y direction. Since the gray solid electrodes are required, the electrodes that can be selected for activation and heating are white hollow electrodes (a total of N-1). Since the positions of the white hollow electrodes are fixed, the full combination of all white hollow electrodes is the full combination of the lens group:

[0054]

[0055] in It represents single lens imaging, that is, only the gray electrodes E1 and E1 need to be heated. N+1 , without white hollow electrode heating. If the number of optical switches is M, then the number of path combinations of the current optical switch is The number of possible combinations of functions is N! (N factorial).

[0056] refer to Figure 7 In the first direction x, through the multi-stage electrode cascade (L1~L M ), the cascade of lens groups can be further realized to complete a more complex optical switch function. The number and length of the electrodes in the direction x included in each stage can be the same or different.

[0057] The following takes a 3×3 optical switch as an example to specifically introduce the topology architecture and implementation method of an N×N optical switch.

[0058] refer to Figure 8 , a 3×3 optical switch includes 3 input ports (I1, I2, I3) and 3 output ports (O1, O2, O3). To realize a 3×3 non-blocking optical switch, the number of all possible functional combinations is 6 (3!), and the specific mapping relationship is shown in Table 1. For ease of explanation, the subsequent port numbers are uniformly represented by digital arrangement (input-output mapping in Table 1), for example, 231 means that the optical signal of the port from top to bottom comes from input ports I2, I3, I1. Therefore, the transformation 123→213 means I1→O2, I2→O1, I3→O3.

[0059] Table 1 Mapping diagram of all achievable output combinations of 3×3 optical switches

[0060] Serial number Input port-output port Input-Output Mapping ① <![CDATA[I1→O1,I2→O2,I3→O3]]> 123→123 ② <![CDATA[I1→O1,I2→O3,I3→O2]]> 123→132 ③ <![CDATA[I1→O2,I2→O1,I3→O3]]> 123→213 ④ <![CDATA[I1→O3,I2→O1,I3→O2]]> 123→231 ⑤ <![CDATA[I1→O2,I2→O3,I3→O1]]> 123→231 ⑥ <![CDATA[I1→O3,I2→O2,I3→O1]]> 123→321

[0061] It is understandable that a single lens can only achieve symmetrical exchange of port signals or keep them unchanged ( Figure 5 Not all output combinations can be achieved by a single-stage lens group. In a 3×3 optical switch, there are four functions that can be achieved by a single stage (Formula 1, 2 N-1 , 2 2 ),like Fig. 9 As shown, that is ①123→123, ②123→132, ③123→213 and ⑥123→321.

[0062] refer to Fig.10 ④123→231 and ⑤123→312 require two-stage lens group cascade to achieve, so if you want to realize a 3×3 non-blocking optical switch, at least two stages of cascade are required. It should be noted that Fig.10 Only one of the cascade implementation methods for realizing the above two output combinations is given. In the two-stage cascade, all possible lens group combinations (4 2 , a total of 16 types) refer to Table 1.

[0063] There are 6 possible combinations of functions for a 3×3 non-blocking optical switch, and 16 possible combinations of lens groups. Therefore, there are combinations of lens groups that repeatedly implement the same optical switch function, as shown in Table 2. This increases the robustness of the optical switch. To further illustrate the above lens group cascade combination, Fig.11 The simulation results for all six optical switch functional combinations are shown. Fig.12 The output spot distribution results of a 3×3 non-blocking optical switch chip measured experimentally are demonstrated, which more fully illustrates the feasibility of N×N optical switch.

[0064] Table 2 Mapping table of all achievable output combinations of 2-stage cascaded 3×3 optical switches

[0065]

[0066] By calculation, when multiple stages are cascaded, the total number of optical switch function combinations that can be realized in each stage of N×N optical switches (without duplication) is as follows: Fig.13 As shown. It can be seen that the number of combinations that can be realized at the first level is the number of functional combinations that can be realized at a single level (Formula 1, 2 N-1 ), and the minimum number of cascade stages required to realize all optical switch function combinations is (Round up). In actual design, there are some symmetrical switching combinations that cannot be achieved with a single-stage lens. In this case, more stages are required to satisfy all combinations of optical switch outputs. In particular, the lens combination of 1×1 and 2×2 ports can easily cover all path combinations of N×N optical switches, similar to the N×N optical switch network architecture built using MZI unit devices. In this case, the minimum number of cascade stages required is N.

[0067] The design method of the N×N optical switch architecture specifically includes the following steps:

[0068] Step 1: Determine the number of ports required (N×N); calculate all optical switch function combinations and quantities (N!) of the current number of ports, or obtain the required optical switch function combinations for practical applications. For the convenience of description, it is uniformly recorded as the target optical switch function combination quantity O tar ,For example Figure 8 and Fig. 9 All 6 optical switch function combinations of the 3×3 optical switch shown in the figure;

[0069] Step 2: Arrange N input ports and N output ports at equal intervals, and arrange the first-level strip electrode array according to the positions of the input ports and output ports, calculate all lens group combinations T of the first-level strip electrode array and their number of combinations; the maximum number of optical switch function combinations that can be realized in a single stage (2 N-1 );For example Fig.10 The four single stages of the 3×3 optical switch shown in the figure can realize the combination of optical switch functions.

[0070] Step 3: Determine all combinations T of the current strip electrode array and the target path combination O tar Are they the same? If T=O tar , then the arrangement of the strip electrode array is completed, and step five is executed; otherwise, a strip electrode array is added on the basis of the current condition electrode array, and step four is executed;

[0071] Step 4: Substitute all output path combinations of the previous strip electrode array into the input of the newly added strip electrode array, update all combinations T of the current strip electrode array, and return to step 3;

[0072] Step 5: Generate a mapping table of driving strip electrode configuration and output optical switch function, as shown in Table 2. By searching the mapping table of target optical switch function and electrode configuration, all functions of the N×N optical switch can be realized.

[0073] In summary, the present application provides an N×N optical switch architecture and implementation method, which belongs to the field of optical communication technology. The optical switch device adopts a multi-stage thermal optical waveguide lens group cascade structure, and modulates the propagation path of the light field by multi-stage strip electrodes arranged around the multi-mode waveguide, thereby realizing a non-blocking N×N optical switch function. The N×N optical switch device can effectively solve the problems of complex driving, high loss, and high cost of on-chip optical switch devices, and realize large-port, wavelength-independent, and polarization-independent arbitrary non-blocking N×N optical switch functions.

[0074] Those skilled in the art can understand that the above are only preferred examples of the invention and are not intended to limit the invention. Although the invention is described in detail with reference to the above examples, those skilled in the art can still modify the technical solutions recorded in the above examples or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the invention shall be included in the protection scope of the invention.

Claims

1. An N×N optical switch architecture, characterized in that: It includes N input waveguides, one multimode waveguide and N output waveguides, and a plurality of strip electrodes located in the multimode waveguide area; The input end of the input waveguide is connected to the input optical fiber array, the output end of the input waveguide is connected to the input end of the multimode waveguide; the output end of the multimode waveguide is connected to the input end of the output waveguide; the output end of the output waveguide is connected to the output optical fiber array; the input waveguide, the multimode waveguide and the output waveguide are all made of materials with thermo-optical effect; In the waveguide plane, the direction of light beam transmission is defined as the x direction, and the direction perpendicular to the x direction is the y direction. N input waveguides and N output waveguides are arranged at equal intervals along the y direction, and each input port and the output port corresponding to the x direction form a pair of input-output port combinations; The plurality of strip electrodes are arranged in an array of (N+1)×M in the multimode waveguide region, the N+1 strip electrodes in each column form a single-stage strip electrode array, and the N+1 strip electrodes in each column are symmetrically arranged with the center line of the N pairs of input-output port combinations as the symmetry center; M represents the number of cascades of the optical switch, A thermo-optical waveguide lens or a thermo-optical waveguide lens group is constructed through the thermo-optical effect of the strip electrodes to regulate the light field propagation path and realize the optical signal switching function.

2. The N×N optical switch architecture according to claim 1, characterized in that: The N×N optical switch architecture further includes a first cladding layer, a first core layer, and a second cladding layer; the first core layer is located between the first cladding layer and the second cladding layer, and the input waveguide, the multimode waveguide, and the output waveguide are all located in the core layer.

3. The N×N optical switch architecture according to claim 1, wherein: The refractive index of the first core layer is greater than the refractive index of the first cladding layer and the second cladding layer.

4. The N×N optical switch architecture according to claim 1, wherein: The input waveguide includes a single-mode straight waveguide, a wedge-shaped waveguide and a single-mode bent waveguide.

5. The N×N optical switch architecture according to claim 1, characterized in that: The output waveguides include single-mode straight waveguides, wedge-shaped waveguides and single-mode bent waveguides.

6. A method for designing an N×N optical switch architecture as claimed in claim 1, characterized in that: The steps include: Step 1: Calculate the target path combination O required by the N×N optical switch ports tar , the number is N! ; Step 2: Arrange N input ports and N output ports at equal intervals, and arrange the first-level strip electrode array according to the positions of the input ports and the output ports, and calculate all lens group combinations T and the number of combinations of the first-level strip electrode array; Step 3: Determine all combinations T of the current strip electrode array and the target path combination O tar Are they the same? If T=O tar , then the arrangement of the strip electrode array is completed, and step five is executed; otherwise, a strip electrode array is added on the basis of the current condition electrode array, and step four is executed; Step 4: Substitute all output path combinations of the previous strip electrode array into the input of the newly added strip electrode array, update all combinations T of the current strip electrode array, and return to step 3; Step 5: Generate a mapping table of driving strip electrode configuration and output optical switch function.

7. An N×N optical switch array, characterized in that: The N×N optical switch array is implemented based on the N×N optical switch architecture according to claim 1; The multimode waveguide is a three-dimensional multimode waveguide; Along the z direction which is perpendicular to both the x direction and the y direction, there are P layers of (N+1)×M strip electrode arrays and P layers of N pairs of input and output port combinations, and each layer of strip electrode arrays and N pairs of input and output port combinations are the same as the arrangement in the N×N optical switch architecture described in claim 1.

Images