A small broadband, high robustness topology photonic crystal routing device

Abstract

The application discloses a small broadband high-robustness topological photonic crystal routing device, which comprises a substrate, a signal input waveguide, a topological photonic crystal waveguide and a routing area; the signal input waveguide, the topological photonic crystal waveguide and the routing area are arranged on the substrate; the routing area is connected between the signal input waveguide and the topological photonic crystal through a robust-inverse design method; a TE0 mode signal is input through a signal different input waveguide, and is converted into a specified pseudo-spin mode signal after passing through the routing area and is output from a corresponding topological photonic crystal waveguide. The application performs topological optimization inverse design on the routing device based on the robust-inverse design method, so that the broadband high-robustness topological photonic crystal routing function is realized, and the problems of large insertion loss, unstable performance, low robustness and narrow bandwidth in the traditional on-chip topological photonic crystal routing device are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of optical communication technology, and particularly relates to a small-sized sulfide broadband topological photonic crystal router device based on robust-inverse design. BACKGROUND

[0002] In the past few decades, with the progress and development of society, higher requirements are put forward for information, and miniaturization and integration have become the development trend in the field of information hardware. The requirement for the environment during signal transmission is extremely high, and backscattering will significantly affect the transmission quality and distance of the signal. Topological photonic crystals have become the focus of development due to their unique single transmission property.

[0003] In the topological photonic crystal, the mode in the waveguide is fixed, which makes it impossible to flexibly configure the topological photonic crystal in the existing optical network system. At the same time, in the traditional integrated optical circuit, the signal is usually transmitted in the form of a single-mode signal. At present, there is no topological photonic crystal router device that can be practically applied.

[0004] In addition, unlike the traditional near-infrared waveband, the mid-infrared, as an optical waveband with great scientific and engineering value, covers most of the important biological and chemical molecular absorption fingerprints and contains multiple atmospheric windows, and plays a crucial role in biochemical sensing, infrared imaging, space communication, medical treatment and military. All these applications cannot be separated from the development of integrated photonic devices, which provides great impetus for the research of mid-infrared integrated chip devices. The mid-infrared on-chip integrated optical device can greatly improve the performance of the mid-infrared application system, reduce the system size and cost, and lay a foundation for the wide application of mid-infrared functional devices.

[0005] Traditional mid-infrared integrated devices mainly have silicon, sulfide glass and halide glass as the material platform, but single material is faced with the problems of high preparation cost and limited working bandwidth, and a new type of multi-material integrated mid-infrared platform is urgently needed. At the same time, the increase of the working wavelength also brings the increase of the mode field area and more mode field leakage, which makes the integration of mid-infrared photonic devices challenging.

[0006] Furthermore, traditional topological photonic crystal routers require strict fabrication and arrangement, introducing significant insertion loss. They also suffer from drawbacks such as large size, small operating bandwidth, and lack of functional flexibility, hindering miniaturization and integration. Moreover, all designs are based on silicon-based photonic devices operating in the near-infrared band; the design of topological photonic crystal routers in the mid-infrared band, with a wavelength centered at 2000 nm, is completely unexplored. Therefore, achieving miniaturization, improving performance, and designing chalcogenide topological photonic crystal routers with high conversion efficiency, low insertion loss, and large operating bandwidth is crucial and extremely challenging. Summary of the Invention

[0007] To address the problems existing in the background art, the purpose of this invention is to provide a small, robust, reverse-designed chalcogenide broadband, highly robust topological photonic crystal router device, thereby overcoming the deficiencies of the prior art.

[0008] This invention relates to a photonic device based on chalcogenide media that enables low-loss signal transmission in the mid-infrared band. A TEO mode signal is input through different waveguides, passes through a routing region, and is converted into a specified pseudospin mode signal, which is then output from the corresponding topological photonic crystal waveguide. This invention utilizes a robust-reverse design method to perform topology optimization and reverse design on the device, enabling it to achieve broadband, highly robust topological photonic crystal routing functionality. This addresses the problems of high insertion loss, unstable performance, low robustness, and narrow bandwidth inherent in traditional on-chip topological photonic crystal routing devices.

[0009] The technical solution adopted in this invention includes:

[0010] Substrate;

[0011] A signal input waveguide is disposed on the substrate, including a first input waveguide and a second input waveguide, wherein the first input waveguide and the second input waveguide have the same structure and are arranged at intervals.

[0012] Multiple topological photonic crystals are arranged on the substrate, including a first topological photonic crystal waveguide and a second topological photonic crystal waveguide. The first and second topological photonic crystal waveguides are distributed as two ports of the router device. In practical applications, more topological photonic crystal waveguides can be used to form more ports.

[0013] A routing region is disposed on the substrate and is constructed and connected between the signal input waveguide and the topological photonic crystal through robust-reverse design.

[0014] The TE0 mode signal is input from different signal input waveguides, and after passing through the routing area, it is converted into the corresponding pseudo-spin mode signal and output from the corresponding topological photonic crystal; or the pseudo-spin mode signal is input through the topological photonic crystal, and after passing through the routing area, it is converted into the corresponding TE0 mode signal and output from the corresponding signal input waveguide.

[0015] The substrate is made of silicon dioxide, and both the signal input waveguide and the topological photonic crystal are made of chalcogenide glass. Chalcogenide materials possess numerous photosensitive properties, a wide infrared window, and high optical nonlinearity, enabling the device to operate with low loss in the infrared band.

[0016] The signal input waveguide, the topological photonic crystal, and the routing region are arranged sequentially along the signal transmission direction. The first and second input waveguides of the signal input waveguide and the first and second topological photonic crystal waveguides of the topological photonic crystal are respectively arranged on both sides of the centerline along the signal transmission direction.

[0017] The first and second topological photonic crystal waveguides are symmetrically distributed.

[0018] In this invention, "small" refers to a size of less than 5*5 micrometers.

[0019] In this invention, "broadband" refers to a working bandwidth of 100 nanometers or more.

[0020] The routing area is divided into n*n unit cubes in three-dimensional space. Each unit cube has only two possible material states: air or chalcogenide glass. That is, each unit cube is only made of air or chalcogenide glass.

[0021] The routing area was determined through a robust-reverse design approach, specifically by optimizing it in the following way:

[0022] The objective function is established based on the ratio between the signal energy of the pseudospin mode output by the topological photonic crystal and the signal energy of the TEO mode in the signal input waveguide under different routing operating conditions:

[0023] min(FOM0(ε(device))-1)

[0024]

[0025] In the formula, min(FOM0(ε(device))-1) represents the objective function of the router device under ideal conditions. N represents the total number of working scenarios in which the device's routing function is implemented, and E 赝自旋 (i) represents the electric field intensity of the pseudo-spin mode in the corresponding topological photonic crystal waveguide under the i-th routing scenario, E TE模式(i) represents the electric field strength of the input signal in the corresponding signal input waveguide under the i-th routing working scenario, i represents the specified routing working scenario, and ε (device) represents the overall dielectric constant distribution of the routing region;

[0026] Based on the above objective function, establish the routing objectives and relationships for the entire device. Solve the problem under the objective function to obtain the optimal distribution of dielectric constants of each unit cube, and then construct the routing area according to the optimal distribution.

[0027] During the optimization process, when the number of iterations to be solved reaches a preset threshold, error analysis (refractive index, distribution, etc.) is introduced into the optimization process. An error disturbance is introduced to establish a robust-reverse design optimization model according to the following formula. This robust-reverse design optimization model is then used to replace the objective function for further iterative optimization, solving for the final dielectric constant distribution ε(P), thus achieving robust reverse design.

[0028] Specifically, the robust optimization design is carried out in the following way:

[0029]

[0030] FOM * (ε(device),ξ)=FOM0(ε(device)+ξ(ε(device)))

[0031] In the formula, ε(device) represents the dielectric constant distribution of the entire routing region, and FOM0(v(device)) represents the objective function of the entire routing region under ideal conditions; FOM * (ε(device), ξ) represents the objective function of the entire routing area under error perturbation; ξ represents the preset error perturbation factor of the entire routing area, such as processing error, temperature error, etc.; ξ(ε(device)) represents the change in the dielectric constant distribution of the structure of the entire routing area under error perturbation; E ξ [(FOM * (ε(device), ξ)-FOM0(ε(device))) 2 ] represents the expected variance of the device objective function with respect to the ideal objective function under the influence of error; β represents the number of iterations in the optimization process, and β0 represents the threshold number of iterations in the optimization process.

[0032] This invention uses an objective function to measure device performance. The objective function, denoted as FOM, is the sum of the ratios between the signal energy of the pseudospin mode output by the topological photonic crystal and the signal energy of the TEO mode in the device's signal input waveguide under different routing operating states. When the device achieves correct routing, i.e., the FOM should approach 1, enabling the device to achieve broadband mode switching with a center wavelength of 2000 nm, the objective function needs to satisfy certain relationships.

[0033] The routing region is spatially divided into 250*250 unit structures, each with dimensions of 20*20*500nm. Each unit structure has two possible material properties: air or chalcogenide glass. The combination of all unit structures' material properties forms the structural shape of the routing region, resulting in a total of 2... 62500 A number of possible structural arrangements.

[0034] First, based on the device's function, an objective function and initial conditions are established. Then, using the adjoint method, the relationship between the objective function and the dielectric constant within each unit structure is established, and the gradient relationship of the dielectric constant for each unit structure satisfying the objective function relationship is solved. During the adjoint method solution process, the change in dielectric constant of each cell is allowed to be continuous. Through iterative processing using the gradient relationship, the optimal distribution of dielectric constants in space is obtained. Since the dielectric constant in the actual structure exists in two discrete states, further projection and filtering of the spatial dielectric constant distribution are performed. It is worth noting that mid-infrared devices are easily affected by factors such as temperature and processing errors, and the device often has many constraints. However, considering these constraints from the outset would excessively increase optimization time and computational requirements. Here, modified constraints are introduced during the projection process to increase device robustness without affecting computational requirements. The discrete dielectric constant distribution in space, i.e., the material properties of each cell, is determined, ultimately defining the structure of the design area.

[0035] The technical solution of the present invention has the following beneficial effects:

[0036] This invention utilizes a continuous parameter adjoint source optimization method to achieve reverse design of mid-infrared devices, enabling signal processing with specified functions, including but not limited to multi-functional mode conversion. It overcomes the problems of large structural size, difficulty in integration, and narrow operating bandwidth of traditional mid-infrared optical devices, filling the gap in the design of chalcogenide mode conversion devices.

[0037] This invention establishes a robust-reverse design optimization model, introduces an error perturbation term during the optimization process, and improves the robustness and reliability of the design by optimizing the expected variance of the objective function of the device under different error conditions. It overcomes the problem of traditional reverse design getting trapped in local optima and proposes a new optimization model.

[0038] This invention includes a photonic device based on a multi-material integrated platform to realize the function of mid-infrared long-wave low-loss signal transmission. The device is reverse-engineered by topology optimization based on the adjoint source method to realize the specified functions, including but not limited to multi-functional mode conversion. This solves the problems of high loss, high cost, large footprint and unstable performance in traditional mid-infrared on-chip devices.

[0039] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0040] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0041] Figure 1 This is a schematic diagram illustrating the structure of a small, broadband, highly robust topological photonic crystal router according to an exemplary embodiment.

[0042] Figure 2 This is a schematic cross-sectional view of an input waveguide and a topological photonic crystal according to an exemplary embodiment.

[0043] Figure 3 This is a schematic diagram of the routing area of ​​a small broadband, highly robust topology photonic crystal router according to an exemplary embodiment.

[0044] Figure 4 This is a flowchart illustrating a robust reverse engineering method according to an exemplary implementation.

[0045] Figure 5 This is an electric field distribution diagram of different waveguide modes in the cross-section of the input waveguide and the topological photonic crystal, according to an exemplary embodiment.

[0046] Figure 6 This is an electric field distribution diagram of a device at the operating wavelength, illustrated according to an exemplary embodiment.

[0047] Figure 7 The example embodiment illustrates the signal transmission rates of the first topological photonic crystal waveguide and the second photonic crystal waveguide when a signal is input from the first input waveguide.

[0048] In the figure: substrate (1), first signal input waveguide (21), second signal input waveguide (22), first topological photonic crystal waveguide (31), second topological photonic crystal waveguide (32), routing region (4). Detailed Implementation

[0049] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0050] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0051] like Figure 1 As shown, the structure of the specific implementation device includes:

[0052] Substrate 1;

[0053] The signal input waveguide 2 is arranged on the substrate 1 and includes a first input waveguide 21 and a second input waveguide 22. The first input waveguide 21 and the second input waveguide 22 have the same structure and are arranged at intervals.

[0054] A topological photonic crystal 3 is disposed on a substrate 1 and includes a first topological photonic crystal waveguide 31 and a second topological photonic crystal waveguide 32. The first topological photonic crystal waveguide 31 and the second topological photonic crystal waveguide 32 are distributed as two ports of a router device and are symmetrically distributed.

[0055] In practical applications, more ports can be formed by using more topological photonic crystal waveguides;

[0056] Routing region 4 is arranged on substrate 1 and is constructed and connected between signal input waveguide 2 and topological photonic crystal 3 through robust-reverse design.

[0057] The TE0 mode signal is input from different signal input waveguide 2, and after passing through the routing region 4, it is converted into the corresponding pseudo-spin mode signal and output from the corresponding topological photonic crystal 3; the pseudo-spin mode signal is input through the topological photonic crystal 3, and after passing through the routing region 4, it is converted into the corresponding TE0 mode signal and output from the corresponding signal input waveguide 2.

[0058] In the specific implementation, substrate 1 is made of silicon dioxide, and both signal input waveguide 2 and topological photonic crystal 3 are made of chalcogenide glass. Due to their numerous photosensitivity, wide infrared window, and high optical nonlinearity, chalcogenide materials enable the device to operate with low loss in the infrared band.

[0059] In practice, the width W_input of the signal input waveguide is 900 nanometers and the thickness H is 500 nanometers.

[0060] In practice, the macropore diameter R of the topological photonic crystal is 296 nanometers, the micropore diameter r is 133 nanometers, and the thickness H is 500 nanometers.

[0061] The routing region 4 is divided into n*n unit cubes in three-dimensional space. Each unit cube has two possible material states: air or chalcogenide glass. That is, each unit cube is only made of air or chalcogenide glass.

[0062] In practice, routing region 4 has a width of 5 micrometers, a length of 5 micrometers, and a thickness H0 of 500 nanometers. Routing region 4 is divided into 250*250 unit cubes, each unit cube having a length of 20 nanometers, a width of 20 nanometers, and a thickness of 500 nanometers.

[0063] Each unit cube in the routing region has two possible material states: air or chalcogenide glass.

[0064] Routing area 4 was determined through a robust-reverse design approach, specifically by optimizing it in the following way:

[0065] Based on the ratio between the signal energy of the pseudospin mode output by the topological photonic crystal (3) and the signal energy of the TEO mode in the signal input waveguide (2) under different routing operating states, the objective function is established:

[0066] min(FOM0(ε(device))-1)

[0067]

[0068] In the formula, min(FOM0(ε(device))-1) represents the objective function of the router device under ideal conditions. N represents the total number of working scenarios in which the device's routing function is implemented, and E 赝自旋 (i) represents the electric field intensity of the pseudo-spin mode in the corresponding topological photonic crystal waveguide (3) under the i-th routing scenario, E TE模式 (i) represents the electric field strength of the input signal in the corresponding signal input waveguide (2) under the i-th routing working scenario, i represents the specified routing working scenario, and ε (device) represents the dielectric constant distribution of the routing region (4) in space.

[0069] Based on the above objective function, establish the routing objectives and relationships for the entire device. Solve under the objective function to obtain the optimal distribution of dielectric constants of each unit cube, and then construct routing region 4 according to the optimal distribution.

[0070] During the optimization process, when the number of iterations to be solved reaches a preset threshold, error analysis (refractive index, distribution, etc.) is introduced into the optimization process. An error disturbance is introduced to establish a robust-reverse design optimization model according to the following formula. This robust-reverse design optimization model is then used to replace the objective function for further iterative optimization, solving for the final dielectric constant distribution ε(P), thus achieving robust reverse design.

[0071] Specifically, the robust optimization design is carried out in the following way:

[0072]

[0073] FOM * (ε(device),ξ)=FOM0(ε(device)+ξ(ε(device)))

[0074] In the formula, ε(device) represents the dielectric constant distribution of the overall structure of the routing region (4), and FOM0(ε(device)) represents the objective function of the overall routing device under ideal conditions; FOM * (ε(device), ξ) represents the objective function of the overall router device under error disturbance; ξ represents the preset error disturbance factor of the overall router device, such as manufacturing error, temperature error, etc.; ξ(ε(device)) represents the change in the dielectric constant distribution of the overall router device structure under error disturbance; E ξ [(FOM * (ε(device)εξ)-FOM0(ε(device))) 2 ] represents the expected variance of the device objective function with respect to the ideal objective function under the influence of error; β represents the number of iterations in the optimization process, and β0 represents the threshold number of iterations in the optimization process.

[0075] In this embodiment, Figure 2 This is a schematic cross-sectional view of an input waveguide and a topological photonic crystal according to one embodiment. Specifically, the width W_input of the signal input waveguide is 900 nm, and the thickness H is 500 nm. The large aperture diameter R of the topological photonic crystal is 296 nm, the small aperture diameter r is 133 nm, and the thickness H is 500 nm.

[0076] In this embodiment, Figure 3 This is a schematic diagram of the routing area of ​​a small, broadband, highly robust topological photonic crystal router according to an exemplary embodiment. The routing area is spatially divided into 250*250 = 62,500 unit structures, each with dimensions of 20*20*500 nm. Each unit structure has two possible material properties: air or chalcogenide glass. The material properties of all unit structures are combined to form the structural shape of the routing area, which has a total of 2 62500There are several possible structural arrangements. Each structural arrangement corresponds to a set of objective functions.

[0077] In this embodiment, Figure 4 This is a flowchart illustrating a reverse design method for topology optimization based on an exemplary implementation. Based on the device function, an objective function and initial conditions are established. Using the adjoint method, the relationship between the objective function and the dielectric constant within each unit structure is established, and the gradient relationship of the dielectric constant for each unit structure satisfying the objective function relationship is solved. During the adjoint method solution process, the change in dielectric constant of each cell is allowed to be continuous. Through iterative processing using the gradient relationship, the optimal distribution of dielectric constants in space is obtained. Since the dielectric constant in the actual structure exists in two discrete states, further projection and filtering of the spatial dielectric constant distribution are performed. It is worth noting that mid-infrared devices are easily affected by factors such as temperature and manufacturing errors, and the constraints on the devices are often numerous. However, considering these constraints from the outset would excessively increase the optimization time and computational requirements.

[0078] Here, modified constraints are introduced during the projection process to increase device robustness without affecting computing power requirements. A robust-reverse design optimization model is established, incorporating robust design into the optimization process. When the number of optimization iterations reaches a certain preset threshold, error analysis is introduced into the optimization process. The robust-reverse design optimization model is then used to replace the objective function for further iterative optimization, achieving robust reverse design.

[0079] This allows for the determination of device designs that allow for greater processing errors, operating temperatures, and suitability for complex environments. Furthermore, it determines the discrete dielectric constant distribution in space, i.e., the material properties of each cell, and finally determines the structure of the reverse design region.

[0080] In this embodiment, Figure 5 This is an example embodiment showing the electric field distribution of the output waveguide and topological photonic crystal cross-section at a working wavelength of 2025 nm in different modes. After determining the structural dimensions and material properties of the input waveguide, simulations were performed on the input waveguide and topological photonic crystal. The electric field distribution of the waveguide cross-section TE0 and pseudospin mode at the working wavelength (2025 nm) is shown in the figure.

[0081] In this embodiment, Figure 6 This diagram illustrates the structural electric field distribution at the operating wavelength according to an exemplary embodiment. The results show that when a TEO mode signal is input through the first input waveguide, it is converted into a specified pseudo-spin mode (left-handed / right-handed) signal after passing through the routing region and output from the corresponding topological photonic crystal waveguide. If the pseudo-spin mode signal is input in the reverse direction through the topological photonic crystal, it is converted into a TEO mode signal after passing through the routing region and output from the corresponding input waveguide.

[0082] In this embodiment, Figure 7This is an exemplary embodiment illustrating the transmission rates of different topological photonic crystal waveguides after a signal is input from the first output waveguide. It can be seen that when the device operates in "parallel transmission" mode, the device primarily outputs from the first topological photonic crystal waveguide, achieving a transmission efficiency of nearly 100%. The results demonstrate that the device achieves a high conversion efficiency, low insertion loss, and large operating bandwidth routing function.

[0083] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0084] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A small, broadband, highly robust topological photonic crystal router device, characterized in that, include: Substrate (1); Signal input waveguide (2) is arranged on the substrate (1) and includes a first input waveguide (21) and a second input waveguide (22). The first input waveguide (21) and the second input waveguide (22) have the same structure and are arranged at intervals. Multiple topological photonic crystals (3) are arranged on the substrate (1), including a first topological photonic crystal waveguide (31) and a second topological photonic crystal waveguide (32); The routing region (4) is arranged on the substrate (1) and is constructed by robust-reverse design and connected between the signal input waveguide (2) and the topological photonic crystal (3); The TE0 mode signal is input from different signal input waveguides (2), and after passing through the routing region (4), it is converted into the corresponding pseudo-spin mode signal and output from the corresponding topological photonic crystal (3); or the pseudo-spin mode signal is input through the topological photonic crystal (3), and after passing through the routing region (4), it is converted into the corresponding TE0 mode signal and output from the corresponding signal input waveguide (2). The routing area (4) is determined through a robust-reverse design method, specifically by optimizing it in the following ways: Based on the ratio between the signal energy of the pseudospin mode output by the topological photonic crystal (3) and the signal energy of the TEO mode in the signal input waveguide (2) under different routing operating states, the objective function is established: min(FOM0(ε(device))-1) In the formula, min(FOM0(ε(device))-1) represents the objective function of the router device under ideal conditions; N represents the total number of working scenarios in which the device's routing function is implemented; E 赝自旋 (i) represents the electric field intensity of the pseudo-spin mode in the corresponding topological photonic crystal (3) under the i-th routing scenario, E TE模式 (i) represents the electric field strength of the input signal in the corresponding signal input waveguide (2) under the i-th routing working scenario, i represents the specified routing working scenario, and ε (device) represents the overall dielectric constant distribution of the routing region (4); Under the objective of the above objective function, the optimal distribution of dielectric constant of each unit cube is obtained, and then the routing area (4) is made according to the optimal distribution. During the solution process, when the number of iterations to be solved reaches a preset threshold, an error disturbance is introduced to establish a robust-inverse design optimization model according to the following formula. The robust-inverse design optimization model is then used to replace the objective function for further iterative optimization, thereby achieving robust inverse design: FOM * (ε(device),ξ)=FOM0(ε(device)+ξ(ε(device))) In the formula, ε(device) represents the dielectric constant distribution of the entire routing region (4), and FOM0(ε(device)) represents the objective function of the entire routing region (4) under ideal conditions; FOM * (ε(device),ξ) represents the objective function of the entire routing region (4) under error perturbation; ξ represents the error perturbation factor of the entire routing region (4); ξ(ε(device)) represents the change in the dielectric constant distribution of the structure of the entire routing region (4) under error perturbation; E ξ [(FOM * (ε(device),ξ)-FOM0(ε(device))) 2 ] represents the expected variance of the device objective function with respect to the ideal objective function under the influence of error; β represents the number of iterations in the optimization process, and β0 represents the threshold number of iterations in the optimization process.

2. The small broadband, highly robust topological photonic crystal router device according to claim 1, characterized in that, The substrate (1) is made of silicon dioxide, and the signal input waveguide (2) and the topological photonic crystal (3) are both made of chalcogenide glass.

3. The small broadband, highly robust topological photonic crystal router device according to claim 1, characterized in that, The first topological photonic crystal waveguide (31) and the second topological photonic crystal waveguide (32) are symmetrically distributed.

4. The small broadband, highly robust topological photonic crystal router device according to claim 1, characterized in that: The routing area (4) is divided into n*n unit cubes in three-dimensional space, and each unit cube has only two possible material states: air or chalcogenide glass.

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