Grating structure generation method and device, grating coupler, computer readable storage medium

Abstract

The application relates to a grating structure generation method and device, a grating coupler and a computer readable storage medium, comprising: performing initial structure optimization processing on a preset grating structure in a grating generation area to obtain a plurality of first grating structures, the first grating structure having a first initial structure and a second initial structure; comparing the first initial structure of each first grating structure with a preset first structure parameter to obtain a structure comparison result; performing structure processing on the first initial structure of the plurality of first grating structures based on the structure comparison result to obtain a second grating structure; and performing secondary structure optimization processing on the second initial structure of the second grating structure to obtain a target grating structure. The grating structure generation method and device, the grating coupler and the computer readable storage medium realize the performance balance between coupling efficiency and bandwidth.

Description

Technical Field

[0001] This application relates to the field of integrated optoelectronic technology, and in particular to a method and apparatus for generating grating structures, a grating coupler, and a computer-readable storage medium. Background Technology

[0002] With the rapid growth of data center traffic, the demand for optical input / output density and bandwidth of photonic integrated circuits (PICs) continues to rise. Traditional single-core optical fibers, limited by their physical characteristics, are unable to meet the demands of high-speed, high-capacity data transmission, and are gradually becoming a major bottleneck restricting system performance improvement.

[0003] To address the aforementioned issues, multi-core fiber (MCF) technology based on space division multiplexing (SDM) has been proposed. This technology significantly improves fiber transmission capacity by integrating multiple spatial channels within a single fiber, providing a new development path for overcoming bandwidth bottlenecks. However, multi-core fiber technology still faces a key challenge in its application: how to achieve efficient coupling between photonic chips and multi-core fibers.

[0004] Among existing coupling schemes, vertical grating couplers are considered the core device for solving this problem due to their advantages such as compact structure, large angle tolerance, and compatibility with wafer-level packaging. Meanwhile, silicon-based photonic integration platforms have become the mainstream solution for realizing photonic integrated circuits due to their high refractive index contrast, compatibility with CMOS processes, and high integration density. However, in silicon-on-insulator (SOI) platforms, traditional vertical grating couplers still have the following shortcomings due to the high refractive index characteristics: limited coupling efficiency, typically below 50%; complex three-dimensional structures required for design, leading to significant manufacturing difficulties; and difficulty in adapting to the high-density coupling requirements of multi-core fiber arrays.

[0005] To address the aforementioned issues, existing technologies have proposed a series of improvement methods. For example, these include reducing losses by introducing Bragg mirrors or metal mirrors beneath the grating; improving the light field distribution through silicon overlays; achieving finer grating structures using multi-etching processes; enhancing mode matching with gradient gratings; and introducing intelligent optimization algorithms to increase design freedom. With these methods, some solutions have achieved coupling efficiencies exceeding 50%.

[0006] However, existing technologies still have significant limitations. First, most research focuses on optimizing a single etching depth, while lacking compatibility with the multiple etching depths supported in multi-project wafer (MPW) processes, resulting in poor manufacturing flexibility and high costs. Second, existing vertical grating couplers typically struggle to achieve efficiencies exceeding 70% in the C-band and have narrow bandwidths, making it difficult to meet the application requirements of high-efficiency wavelength division multiplexing (WDM) systems.

[0007] Therefore, how to further improve coupling efficiency and broaden the operating bandwidth while ensuring process compatibility and cost control has become a key issue that existing technologies urgently need to address. Summary of the Invention

[0008] Based on this, it is necessary to provide a method and apparatus for generating grating structures, a grating coupler, and a computer-readable storage medium that can improve coupling efficiency, broaden bandwidth, be well compatible with existing processes, and have controllable costs, in order to address the above-mentioned technical problems.

[0009] To achieve the above objectives, this application provides a method for generating a grating structure, the method comprising:

[0010] In the grating generation area, the preset grating structure is subjected to initial structure optimization processing to obtain multiple first grating structures, each of which has a first initial structure and a second initial structure.

[0011] By comparing the first initial structure and the preset first structure parameters of each first grating structure, a structure comparison result is obtained;

[0012] Based on the structural comparison results, the first initial structure of the plurality of first grating structures is processed to obtain the second grating structure;

[0013] The second initial structure of the second grating structure is subjected to secondary structure optimization processing to obtain the target grating structure.

[0014] In one embodiment, the first structural parameter is at least one parameter threshold determined based on at least two target structural parameters, wherein the target structural parameters are parameters supported by the grating structure etching process. The step of comparing the first initial structure of each first grating structure with the preset first structural parameter to obtain a structural comparison result includes:

[0015] The first initial structure of each first grating structure is compared with the at least one parameter threshold to determine the parameter range corresponding to the first initial structure;

[0016] Based on the parameter range, the correspondence between the parameters of the first initial structure and the target structure is determined, and the structure comparison result is obtained.

[0017] In one embodiment, processing the first initial structure of the plurality of first grating structures based on the structural comparison results to obtain a second grating structure includes:

[0018] Based on the target structure parameters corresponding to each of the first initial structures in the structure comparison results, the first initial structures of the plurality of first grating structures are processed to obtain the second grating structure.

[0019] In one embodiment, in the grating generation region, an initial structure optimization process is performed on a preset grating structure to obtain a plurality of first grating structures, including:

[0020] The first etching parameter and the second etching parameter in the preset grating structure are used as initial optimization parameters;

[0021] Based on the preset algorithm, structural optimization processing is performed on the structural parameters to be processed to obtain the first optimization result;

[0022] Based on the first optimization result, the initial optimization parameters are updated;

[0023] Repeat the iterative steps of performing structural optimization processing on the initial optimization parameters based on the preset algorithm to obtain the first optimization result, and updating the initial optimization parameters based on the first optimization result, until the initial optimization parameters reach the preset convergence condition or the maximum number of iterations;

[0024] The initial optimization parameters at which the preset convergence condition or the maximum number of iterations is reached are used as the first grating structure.

[0025] In one embodiment, after processing the first initial structure of the plurality of first grating structures based on the structural comparison results to obtain the second grating structure, the method further includes:

[0026] The second grating structures that are adjacent to each other and have the same first initial structure are merged to obtain the third grating structure;

[0027] The secondary structure optimization process performed on the second initial structure of the second grating structure to obtain the target grating structure includes:

[0028] The second initial structure of the third grating structure is subjected to secondary structural optimization processing to obtain the target grating structure.

[0029] In one embodiment, the secondary structure optimization process performed on the second initial structure of the third grating structure to obtain the target grating structure includes:

[0030] The second initial structure in the third grating structure is used as the secondary optimization parameter;

[0031] Based on a preset algorithm, the secondary optimization parameters are subjected to structural optimization processing to obtain a second optimization result;

[0032] Based on the second optimization result, the secondary optimization parameters are updated;

[0033] Repeat the iterative steps of performing structural optimization processing on the secondary optimization parameters based on the preset algorithm to obtain the second optimization result, and updating the secondary optimization parameters based on the second optimization result, until the secondary optimization parameters reach the preset convergence condition or the maximum number of iterations;

[0034] The secondary optimization parameters that reach the preset convergence condition or the maximum number of iterations are used as the target grating structure.

[0035] In one embodiment, before performing initial structural optimization processing on the preset grating structure in the grating generation region, the method further includes:

[0036] Define the grating generation area and the preset grating structure.

[0037] This application also provides a generating apparatus for performing the grating structure generating method as described in any of the above embodiments, the generating apparatus comprising:

[0038] The first optimization module is used to perform initial structure optimization processing on the preset grating structure in the grating generation area to obtain multiple first grating structures.

[0039] The structure comparison module is used to compare the first initial structure of the first grating structure with the preset first structure parameters to obtain the structure comparison result;

[0040] The structure processing module is used to modify the first initial structure of the first grating structure based on the structure comparison results to obtain the second grating structure.

[0041] The secondary optimization module is used to perform secondary structural optimization processing on the second initial structure of the second grating structure to obtain the target grating structure.

[0042] This application also provides a grating coupler that generates a grating structure using the method described in any of the above embodiments.

[0043] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is used to implement the grating structure generation method as described in any of the above embodiments.

[0044] The aforementioned grating structure generation method and apparatus, grating coupler, and computer-readable storage medium, through initial structural optimization processing of a preset grating structure in the grating generation region, obtain multiple first grating structures, each having a first initial structure and a second initial structure; then, comparing the first initial structure of each first grating structure with preset first structural parameters, a structural comparison result is obtained; based on the structural comparison result, structural processing is performed on the first initial structures of the multiple first grating structures to obtain second grating structures; and secondary structural optimization processing is performed on the second initial structures of the second grating structures to obtain the target grating structure. Therefore, the aforementioned grating structure, generated through multiple optimization processes, balances the design goals of high coupling efficiency and wideband response, achieving a performance balance between coupling efficiency and bandwidth. This overcomes the efficiency-bandwidth limitation bottleneck in traditional grating design, improves optical performance while enhancing process compatibility, significantly reduces fabrication costs and process risks, and accelerates the transformation from structural design to large-scale manufacturing, demonstrating promising industrialization prospects. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a flowchart illustrating a method for generating a grating structure in one embodiment;

[0047] Figure 2 This is a schematic diagram of the cross-sectional structure of the grating coupler in one embodiment;

[0048] Figure 3 This is a top view of the grating coupler in one embodiment;

[0049] Figure 4 The diagram shows the coupling efficiency and back reflection efficiency of the grating coupler in the 1500nm to 1600nm band in one embodiment.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1-Substrate, 2-Buried oxide layer, 3-Waveguide layer, 4-Clad layer. Detailed Implementation

[0052] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0054] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.

[0055] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0056] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0057] In one embodiment, such as Figure 1 As shown, this application provides a method for generating a grating structure, the method comprising:

[0058] Step S1: In the grating generation area, the preset grating structure is subjected to initial structure optimization processing to obtain multiple first grating structures. The first grating structure has a first initial structure and a second initial structure.

[0059] Step S2: Compare the initial structure of each first grating structure with the preset first structure parameters to obtain the structure comparison results;

[0060] Step S3: Based on the structural comparison results, perform structural processing on the first initial structure of multiple first grating structures to obtain the second grating structure;

[0061] Step S4: Perform secondary structure optimization on the second initial structure of the second grating structure to obtain the target grating structure.

[0062] The aforementioned grating structure generation method involves performing initial structure optimization on a preset grating structure within the grating generation region to obtain multiple first grating structures, each possessing a first initial structure and a second initial structure. The first initial structure of each first grating structure is then compared with preset first structure parameters to obtain a structure comparison result. Based on this comparison result, the first initial structures of the multiple first grating structures undergo structural processing to obtain second grating structures. Finally, the second initial structures of the second grating structures undergo secondary structure optimization to obtain the target grating structure. Therefore, this grating structure, generated through multiple optimization processes, balances the design goals of high coupling efficiency and wideband response, achieving a performance balance between coupling efficiency and bandwidth. It overcomes the efficiency-bandwidth limitation bottleneck in traditional grating design, significantly reducing fabrication costs and process risks while improving optical performance, accelerating the transformation from structural design to large-scale manufacturing, and possessing promising industrialization prospects.

[0063] Specifically, please refer to Figure 2 Steps S1 to S2 are executed. In the grating generation area, the preset grating structure is subjected to initial structure optimization processing to obtain multiple first grating structures. Each first grating structure has a first initial structure and a second initial structure.

[0064] In one embodiment, before performing initial structural optimization processing on the preset grating structure in the grating generation region, the method further includes:

[0065] Define the grating generation area and the preset grating structure.

[0066] The grating generation region refers to the coupling region between the silicon-based optical waveguide and the external optical fiber. The total size of the grating generation region is determined comprehensively based on the overall device design requirements, simulation efficiency, and waveguide mode field matching conditions. For example, the lateral dimension (i.e., the length along the coupling direction) of the grating generation region can be set to 10 μm, and the longitudinal dimension (i.e., the width perpendicular to the coupling direction) can be set to 12 μm to achieve effective matching with the mode field of a vertically incident single-mode optical fiber with a diameter of 10 μm.

[0067] Furthermore, it also includes defining preset grating structures in the grating generation region, specifically including defining the first etching parameters, the second etching parameters, and the number of preset grating structures. The preset grating structure consists of multiple diffraction units set in the grating generation region. In actual processes, it is obtained by etching the optical waveguide layer. Therefore, the number of preset grating structures, the etching width of each preset grating structure, and the etching depth all directly affect the diffraction characteristics and coupling performance of the grating structure. Thus, it is necessary to rationally design the number of preset grating structures, the etching width of each preset grating structure, and the etching depth within the grating generation region to achieve efficient energy coupling between the waveguide mode and the fiber mode.

[0068] In one embodiment, the first etching parameter is the initial etching depth, and the second etching parameter is the initial etching width. The initial etching width is used to adjust the local diffraction intensity and mode field matching. It can be uniformly set to a fixed value (such as 90 nm), or it can be set in a linear gradient, periodic variation, or random perturbation manner to enhance model diversity. The initial etching depth value is set within the etchable depth range of the waveguide layer. For example, when the waveguide layer thickness is 220 nm, it can be set to 110 nm (approximately half the waveguide layer thickness). All preset grating structures can use the same depth, or they can be set to an incremental or perturbation distribution to facilitate rapid convergence in subsequent optimization.

[0069] Based on the period of the preset grating structure (e.g., 90~100nm), the grating generation area can be divided into N preset grating structures, which are arranged at equal intervals along the transverse direction (i.e., along the coupling direction), with a quantity of 50~150 (e.g., N=120).

[0070] In one embodiment, before performing initial structural optimization processing on a preset grating structure in the grating generation region to obtain multiple first grating structures, the method further includes: setting an optimization range in conjunction with target process conditions.

[0071] To ensure the manufacturability and process compatibility of subsequent optimization results, and to provide a reliable parameter basis for subsequent optimization and etching depth determination, it is necessary to define the target process conditions before optimization and set the value range of etching parameters such as etching depth and etching width accordingly. For example, during optimization, the range of etching depth is quantified according to the type of process supported (e.g., 70nm, 130nm, 220nm); the etching width must meet the minimum feature size requirement (e.g., ≥90nm); and the waveguide layer thickness serves as a constraint on the maximum etching depth.

[0072] In one embodiment, in the grating generation region, an initial structure optimization process is performed on a preset grating structure to obtain multiple first grating structures, including:

[0073] The first and second etching parameters in the preset grating structure are used as the initial optimization parameters;

[0074] Based on the preset algorithm, the structural parameters to be processed are optimized to obtain the first optimization result;

[0075] Based on the first optimization result, the initial optimization parameters are updated;

[0076] Repeatedly execute the optimization process based on the preset algorithm to obtain the first optimization result and the iterative steps of updating the initial optimization parameters based on the first optimization result, until the initial optimization parameters reach the preset convergence condition or the maximum number of iterations;

[0077] The initial optimization parameters at which the preset convergence condition or the maximum number of iterations is reached are used as the first grating structure.

[0078] The preset algorithm is an inverse optimization algorithm (i.e., the adjoint method). The structural parameters to be processed include etching depth and etching width. Therefore, based on the preset algorithm, the structural parameters to be processed are optimized to obtain the following first optimization results:

[0079] The initial etching depth and initial etching width are jointly optimized using an inverse optimization algorithm (i.e., the adjoint method) to generate the first optimization result.

[0080] In one embodiment, a reverse optimization algorithm is used to jointly optimize the initial etching depth and initial etching width to generate a first optimization result, including:

[0081] The forward light propagation simulation of the grating generation region was performed using the two-dimensional finite-difference time-domain (FDTD) method to obtain the electric and magnetic field distributions and calculate the quality factor (FOM).

[0082] A reverse-injection optical propagation simulation was performed at the output port using the field corresponding to the target mode as the source to obtain the associated field distribution; the target mode is the TE0 mode, which is a specific waveguide transmission mode in the grating coupler.

[0083] By combining the results of forward and backward simulations, the gradient information of the initial etching width and initial etching depth of FOM for each preset grating structure is derived using the adjoint method to obtain the first optimization result.

[0084] Furthermore, the aforementioned inverse optimization algorithm is used to jointly optimize the initial etching depth and initial etching width to generate the first optimization result. Specifically, this includes defining the quality factor (FOM) using the optical power of the TEO mode transmitted to the output waveguide. (1), where It is the cross-section of the output port. and It is a cross section Target electric and magnetic fields in TE0 mode and This represents the actual field at that cross section, with the overline indicating the complex conjugate.

[0085] When adjusting the initial etching depth and initial etching width, the boundary shape of the preset grating structure is in the region. The dielectric constant changes in that region, thus... An induced polarization density is generated on top. This ultimately leads to changes in the quality factor (FOM).

[0086] The variation of FOM can be clearly derived using the adjoint method, as shown in the following formula: ,in Essentially, it's about location. The function of the steady-state electric field at all points in the region All of these can be known from a forward propagation simulation. The above describes retrograde radiation from the same source as in the forward propagation simulation to the optimization point on the output waveguide cross section. The electric field at the location is such that the change in FOM after the boundary shape of the preset grating structure changes can be obtained by simulating the transmission twice in both directions.

[0087] To facilitate optimization, it is necessary to know the FOM regarding the optimization point. The gradient. For regions where the boundary shape of the preset grating structure changes. The integral needs to be performed along the initial boundary. Furthermore, considering the variation of the boundary along the normal direction, it can be rewritten as follows:

[0088] ,in It is a boundary optimization point The magnitude of the deformation in the normal direction. Since the electric field is discontinuous at the device boundary, consider applying the boundary conditions of Maxwell's equations: The tangential component is continuous, while The normal component is also continuous, and the above equation can be expressed in terms of a continuous electric field.

[0089] further, ,in It is the steady-state electric field after the boundary shape of the pre-defined grating structure changes, and the normal direction is from the point where the dielectric constant is The silicon material has a pointing dielectric constant of . The silicon dioxide material. The electric field after the boundary shape of the pre-defined grating structure changes. It can be determined by the initial electric field. as well as Electric displacement vector representation: The adjoint field can also be split in a similar way: ,therefore It can be rewritten as: Therefore, the gradient of the quality factor FOM with respect to each optimization point can be obtained: (2). Therefore, based on the above, the boundary shape of the preset grating structure can be optimized using the FDTD algorithm combined with simulation software. First, a forward transmission simulation and a reverse transmission simulation are performed on the preset grating structure. Then, based on the simulation results, the FOM value is calculated according to formula (1). Further, the value obtained from the forward transmission simulation is extracted. and Calculations yielded and Extracting the reverse simulation results and Calculations yielded and The gradient of the quality factor FOM relative to the optimization point is calculated according to formula (2), which is the first optimization result obtained by performing structural optimization on the corresponding structural parameters to be processed.

[0090] Based on the first optimization result, that is, using the gradient information obtained above, the boundary shape change proportional to the gradient (i.e., gradient descent) can be introduced to make the FOM approach the optimal value, and then the initial optimization parameters can be updated.

[0091] Repeat the above optimization steps iteratively until the initial parameters reach the preset convergence condition or the maximum number of iterations. The preset convergence condition is that the change in the quality factor value obtained in two consecutive iterations is less than 10. -5The optimization steps described above are repeated iteratively. Each iteration includes forward simulation, FOM calculation, backward simulation, gradient extraction, and parameter update. Specifically, the quality factor value (FOM) is used as the objective function, and multiple optimization points are initially set at the diffraction point boundaries. As the initial value, the corresponding gradient can be obtained above, and boundary optimization points can also be set. One of the boundaries is to avoid overly sharp structures affecting device manufacturing; the boundary optimization point is adjusted each time. After optimizing the boundary shape of the preset grating structure, FDTD was re-called for forward and reverse simulations, and the quality factor value FOM and its gradient were recalculated. Optimization was then performed again. After multiple iterations, when the change in the quality factor value FOM between two adjacent iterations was less than 10... -5 When the iteration stops, the optimal value of FOM is output, and the initial optimization parameters at this time are used as the first grating structure. The first grating structure includes a first initial structure and a second initial structure. The first initial structure is optimized based on the first etching parameters, and the second initial structure is optimized based on the second etching parameters. For example, the first initial structure is the etching depth, and the second initial structure is the etching width.

[0092] It should be noted that the above initial structure optimization process is essentially to minimize the objective function using the extracted gradient information. The objective is usually to maximize the power ratio of the target mode of the output waveguide. Therefore, the sign of the quality factor FOM can be flipped first, and -FOM can be used as the objective function. After module optimization, FOM can be used as the output to achieve maximum optimization of the quality factor value FOM.

[0093] The aforementioned initial structure optimization process allows for coordinated adjustment of the parameters of the first and second initial structures, overcoming the limitations of traditional single-variable or unified grating methods. Furthermore, the adjoint method only requires two FDTD simulations to obtain the gradient, which is significantly less expensive than the derivative method for each parameter. In addition, gradient-driven optimization has faster convergence and can generate high-performance preliminary structures, providing a foundation for subsequent fine-tuning.

[0094] Specifically, step S2 is executed to compare the first initial structure of each first grating structure with the preset first structure parameters to obtain the structure comparison results.

[0095] In one embodiment, the first structural parameter is at least one parameter threshold determined based on at least two target structural parameters, where the target structural parameters are parameters supported by the grating structure etching process. A structural comparison result is obtained by comparing the first initial structure of each first grating structure with the preset first structural parameters, including:

[0096] Each initial structure of the first grating structure is compared with at least one parameter threshold to determine the parameter range corresponding to the first initial structure. The parameter threshold is a parameter threshold for the etching depth, and there are multiple parameter thresholds. Each parameter threshold is the median value between two adjacent target structure parameters. For example, if the three manufacturable target structure parameters specified by the wafer fabrication process are 70nm, 130nm, and 220nm, then the median value between two adjacent target structure parameters is set as the parameter threshold, i.e., 35nm (the median value between 0 and 70nm), 100nm (the median value between 70nm and 130nm), and 175nm (the median value between 130nm and 220nm). Therefore, the above parameter ranges are (0nm, 35nm), (35nm, 100nm), (100nm, 175nm), and (>175nm).

[0097] Based on the parameter range, the correspondence between the parameters of the first initial structure and the target structure is determined, and the structure comparison results are obtained. Each initial structure of the first grating structure, i.e., the etching depth, is assigned to the corresponding parameter range. For example, the initial structure less than 35nm is assigned to the 0nm type; the initial structure greater than 35nm and less than 100nm is assigned to the 70nm type; the initial structure greater than 100nm and less than 175nm is assigned to the 130nm type; and the initial structure greater than 175nm is assigned to the 220nm type.

[0098] Table 1

[0099]

[0100] Table 1 shows the structure comparison results obtained after comparing the initial structure parameters with the target structure parameters of multiple first grating structures in this embodiment. It includes the first etching structure of 88 first grating structures, i.e., the etching depth (H). i The value, the second etching structure, namely the etching width (L) i The value indicates that the first grating structure with different second etching structures is classified as the corresponding target structure parameter.

[0101] Specifically, step S3 is executed, and based on the structural comparison results, the first initial structure of multiple first grating structures is processed to obtain the second grating structure.

[0102] In one embodiment, based on the structural comparison results, a first initial structure of multiple first grating structures is processed to obtain a second grating structure, including:

[0103] Based on the target structure parameters corresponding to each first initial structure in the structural comparison results, the first initial structures of multiple first grating structures are processed to obtain the second grating structure. The first initial structure in each first grating structure is corrected to the target structure parameters corresponding to its parameter range. For example, a first initial structure classified as 0nm is corrected to 0nm; a first initial structure classified as 70nm is corrected to 70nm; a first initial structure classified as 130nm is corrected to 130nm; and a first initial structure classified as 220nm is corrected to 220nm.

[0104] In one embodiment, after processing the first initial structure of multiple first grating structures based on the structural comparison results to obtain a second grating structure, the method further includes: merging adjacent second grating structures that have the same first initial structure to obtain a third grating structure. That is, if the first initial structures of multiple adjacent second grating structures are classified with the same target structural parameters, the adjacent second grating structures are merged with their second initial structures and represented by the same first initial structure. This ensures that the impact on coupling performance is controllable or even negligible, thereby reducing the number of grating boundaries, thus reducing manufacturing difficulty, improving lithography stability, further simplifying the design, and improving manufacturing efficiency. It can also further reduce the number of calculations required for subsequent second optimization, improving optimization efficiency.

[0105] Specifically, step S4 is performed to perform secondary structure optimization processing on the second initial structure of the second grating structure to obtain the target grating structure.

[0106] Specifically, performing secondary structural optimization on the second initial structure of the second grating structure to obtain the target grating structure includes: performing secondary structural optimization on the second initial structure of the third grating structure to obtain the target grating structure.

[0107] In one embodiment, a secondary structure optimization process is performed on the second initial structure of the third grating structure to obtain the target grating structure, including:

[0108] The second initial structure in the third grating structure is used as the secondary optimization parameter;

[0109] Based on the preset algorithm, the secondary optimization parameters are structurally optimized to obtain the second optimization result; based on the second optimization result, the secondary optimization parameters are updated.

[0110] Repeat the iterative steps of performing structural optimization on the secondary optimization parameters based on the preset algorithm to obtain the second optimization result, and updating the secondary optimization parameters based on the second optimization result, until the secondary optimization parameters reach the preset convergence condition or the maximum number of iterations;

[0111] The secondary optimization parameters that meet the preset convergence conditions or the maximum number of iterations are used as the target grating structure.

[0112] The second structural optimization process can follow the adjoint method framework of the initial structural optimization process. Gradient information at the etching width is calculated jointly through forward and backward FDTD simulations, and then the etching width is iteratively updated based on the quality factor function (FOM) until the preset convergence condition is met or the maximum number of iterations is reached. In this step, only the second initial structure is continuously optimized, while the quantified etching depth parameter remains unchanged, thereby achieving further improvement in optical performance while ensuring the feasibility of structural fabrication.

[0113] Through the above optimization process, the second initial structure achieves optimal configuration under high-precision control. The final constructed grating structure achieves the peak coupling efficiency and broadband response of the design performance target while ensuring manufacturing feasibility and process constraints. It achieves a balance between optical performance and manufacturing adaptability, breaks through the bottleneck of efficiency-bandwidth limitation in traditional grating design, and significantly reduces fabrication costs and process risks while improving optical performance. It accelerates the transformation from structural design to large-scale manufacturing and has good engineering feasibility and industrialization prospects.

[0114] Furthermore, it should be noted that the above-mentioned grating structure is generated based on the standard SOI platform. Its layered structure from bottom to top consists of: substrate layer, buried oxide layer, waveguide layer, and cladding layer. The grating structure is mainly generated in the waveguide layer to ensure that the generated grating structure has the expected functional effectiveness.

[0115] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 At least some of the steps in the process may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but may be executed at different times. The execution order of these steps or stages is not necessarily sequential, but may be executed in turn or alternately with other steps or at least some of the steps or stages in other steps.

[0116] In one embodiment, this application also provides a grating structure generation apparatus, which is used to perform the grating coupler generation method described in any of the above embodiments. The generation apparatus includes:

[0117] The first optimization module is used to perform initial structure optimization processing on the preset grating structure in the grating generation area to obtain multiple first grating structures.

[0118] The structure comparison module is used to compare the first initial structure of the first grating structure with the preset first structure parameters to obtain the structure comparison result;

[0119] The structure processing module is used to correct the first initial structure of the first grating structure based on the structure comparison results to obtain the second grating structure.

[0120] The secondary optimization module is used to perform secondary structure optimization on the second initial structure of the second grating structure to obtain the target grating structure.

[0121] In one embodiment, the grating structure generation device further includes a region and structure definition module for defining the grating generation region and the preset grating structure, and for setting the basic parameters before performing the initial structure optimization process.

[0122] In one embodiment, the first optimization module includes:

[0123] The initial parameter setting unit is used to take the first etching parameter and the second etching parameter in the preset grating structure as initial optimization parameters;

[0124] The first optimization unit is used to perform structural optimization processing on the initial optimization parameters based on a preset algorithm to obtain the first optimization result;

[0125] The first update unit is used to update the initial optimization parameters based on the first optimization result;

[0126] The first iteration unit is used to repeat the operations of the first optimization subunit and the first update subunit until the initial optimization parameters reach the preset convergence condition or the maximum number of iterations.

[0127] The first result determination unit is used to take the initial optimization parameters when the preset convergence condition or the maximum number of iterations is reached as the first grating structure; wherein the first etching parameter corresponds to the first initial structure and the second etching parameter corresponds to the second initial structure.

[0128] In one embodiment, the structural comparison module includes:

[0129] A parameter threshold determination unit is used to determine a first structural parameter, wherein the first structural parameter is at least one parameter threshold determined based on at least two target structural parameters, and the target structural parameters are parameters supported by the grating structure etching process;

[0130] The parameter interval determination unit is used to compare the first initial structure of each first grating structure with at least one parameter threshold to determine the parameter interval corresponding to the first initial structure.

[0131] The correspondence determination unit is used to determine the correspondence between the parameters of the first initial structure and the target structure based on the parameter range, and to obtain the structure comparison results.

[0132] In one embodiment, the structure processing module includes a structure processing unit, which processes the first initial structure of a plurality of first grating structures according to the target structure parameters corresponding to each first initial structure in the structure comparison result to obtain a second grating structure.

[0133] In one embodiment, the grating structure generation device further includes a structure merging unit, which is used to merge adjacent second grating structures that have the same first initial structure after the structure processing unit obtains the second grating structure, to obtain a third grating structure; the secondary optimization module is specifically used to perform secondary structure optimization processing on the second initial structure of the third grating structure to obtain the target grating structure.

[0134] In one embodiment, the secondary optimization module includes:

[0135] The secondary parameter setting unit is used to take the second initial structure in the third grating structure as the secondary optimization parameter;

[0136] The second optimization unit is used to perform structural optimization processing on the secondary optimization parameters based on a preset algorithm to obtain the second optimization result;

[0137] The second update unit is used to update the secondary optimization parameters based on the second optimization result;

[0138] The second iteration unit is used to repeat the operations of the second optimization subunit and the second update subunit until the secondary optimization parameters reach the preset convergence condition or the maximum number of iterations.

[0139] The second result determination unit is used to take the secondary optimization parameters when the preset convergence condition or the maximum number of iterations is reached as the target grating structure.

[0140] In one embodiment, see Figure 2 and Figure 3As shown, this application also provides a grating coupler, employing a grating structure generated by the method described in any of the above embodiments. The grating coupler includes: a substrate 1, which is a silicon substrate commonly used in modern silicon photonics processes, used to provide structural support; a buried oxide layer 2 located on the substrate 1, the buried oxide layer 2 being an insulating layer with a thickness of 3 μm, serving to suppress leakage during waveguide transmission; a waveguide layer 3 located on the buried oxide layer 2, serving as the main medium for light transmission, constructed using a 220 nm thick silicon layer commonly found in SOI (silicon-insulator-silicon) platforms, the waveguide layer 3 including multiple diffraction units obtained based on the generated target grating structure; and a cladding layer 4, covering the waveguide layer 3, used to provide protection, thermal stability, and refractive index contrast, forming an effective light-guiding environment.

[0141] To verify the actual performance of the designed structure, simulation tests were conducted on the grating coupler fabricated using the aforementioned grating structure. The test results are as follows: Figure 4 As shown, the coupling efficiency at a wavelength of 1540nm (a typical operating wavelength for C-band optical communication) reaches -0.42dB. Based on the decibel-to-power conversion relationship, this can be converted to a coupling efficiency of approximately 91%, indicating that the grating structure can successfully couple most of the input light into the waveguide, exhibiting extremely high optical energy transmission efficiency.

[0142] Furthermore, tests showed that the device's 1dB bandwidth can reach 40nm, meaning that within a wavelength range of 1540nm±20nm, the coupling efficiency decreases by no more than 1dB, maintaining high transmission efficiency. This high coupling efficiency combined with broadband response indicates that the designed grating coupler structure possesses excellent spectral adaptability, making it particularly suitable for multi-wavelength transmission applications such as wavelength division multiplexing (WDM), thus contributing to improved overall communication performance and adaptability of silicon photonics chip systems.

[0143] In one embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0144] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above method embodiments.

[0145] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0146] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate 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, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0147] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0148] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for generating a grating structure, characterized in that, The generation method includes: In the grating generation area, the preset grating structure is subjected to initial structure optimization processing to obtain multiple first grating structures, each of which has a first initial structure and a second initial structure. By comparing the first initial structure and the preset first structure parameters of each first grating structure, a structure comparison result is obtained; The first structural parameter is at least one parameter threshold determined based on at least two target structural parameters, wherein the target structural parameters are parameters supported by the grating structure etching process. The comparison of the first initial structure of each first grating structure with the preset first structural parameter to obtain a structural comparison result includes: The first initial structure of each of the first grating structures is compared with the at least one parameter threshold to determine the parameter range corresponding to the first initial structure; wherein, there are multiple parameter thresholds, and the parameter threshold is the median value between two adjacent target structure parameters among the multiple target structure parameters; Based on the parameter range, determine the correspondence between the parameters of the first initial structure and the target structure, and obtain the structure comparison result; The step of determining the correspondence between the parameters of the first initial structure and the target structure based on the parameter range, and obtaining the structure comparison result, includes: Each initial structure of the first grating structure is assigned to its corresponding parameter range; Based on the structural comparison results, the first initial structure of the plurality of first grating structures is processed to obtain the second grating structure; Based on the structural comparison results, the first initial structure of the plurality of first grating structures is processed to obtain a second grating structure, including: Based on the target structure parameters corresponding to each first initial structure in the structure comparison results, the first initial structures of the plurality of first grating structures are processed to obtain the second grating structure; The step of processing the first initial structure of the plurality of first grating structures according to the target structure parameters corresponding to each first initial structure in the structure comparison result to obtain the second grating structure includes: The initial structure in each first grating structure is corrected to the target structure parameters corresponding to its parameter range; The second initial structure of the second grating structure is subjected to secondary structure optimization processing to obtain the target grating structure.

2. The grating structure generation method according to claim 1, characterized in that, In the grating generation region, an initial structure optimization process is performed on a preset grating structure to obtain multiple first grating structures, including: The first etching parameter and the second etching parameter in the preset grating structure are used as initial optimization parameters; Based on the preset algorithm, structural optimization processing is performed on the structural parameters to be processed to obtain the first optimization result; Based on the first optimization result, the initial optimization parameters are updated; Repeat the iterative steps of performing structural optimization processing on the initial optimization parameters based on the preset algorithm to obtain the first optimization result, and updating the initial optimization parameters based on the first optimization result, until the initial optimization parameters reach the preset convergence condition or the maximum number of iterations; The initial optimization parameters at which the preset convergence condition or the maximum number of iterations is reached are used as the first grating structure.

3. The grating structure generation method according to claim 1, characterized in that, After processing the first initial structure of the plurality of first grating structures based on the structural comparison results to obtain the second grating structure, the process further includes: The second grating structures that are adjacent to each other and have the same first initial structure are merged to obtain the third grating structure; The secondary structure optimization process performed on the second initial structure of the second grating structure to obtain the target grating structure includes: The second initial structure of the third grating structure is subjected to secondary structural optimization processing to obtain the target grating structure.

4. The grating structure generation method according to claim 3, characterized in that, The secondary structure optimization process performed on the second initial structure of the third grating structure to obtain the target grating structure includes: The second initial structure in the third grating structure is used as the secondary optimization parameter; Based on a preset algorithm, the secondary optimization parameters are subjected to structural optimization processing to obtain a second optimization result; Based on the second optimization result, the secondary optimization parameters are updated; Repeat the iterative steps of performing structural optimization processing on the secondary optimization parameters based on the preset algorithm to obtain the second optimization result, and updating the secondary optimization parameters based on the second optimization result, until the secondary optimization parameters reach the preset convergence condition or the maximum number of iterations; The secondary optimization parameters that reach the preset convergence condition or the maximum number of iterations are used as the target grating structure.

5. The grating structure generation method according to claim 1, characterized in that, Before performing initial structural optimization processing on the preset grating structure in the grating generation region, the process further includes: Define the grating generation area and the preset grating structure.

6. A grating structure generation device, characterized in that, The generating apparatus is used to perform the grating structure generating method as described in any one of claims 1 to 5, the generating apparatus comprising: The first optimization module is used to perform initial structure optimization processing on the preset grating structure in the grating generation area to obtain multiple first grating structures. The structure comparison module is used to compare the first initial structure of the first grating structure with the preset first structure parameters to obtain the structure comparison result; The structure processing module is used to modify the first initial structure of the first grating structure based on the structure comparison results to obtain the second grating structure. The secondary optimization module is used to perform secondary structural optimization processing on the second initial structure of the second grating structure to obtain the target grating structure.

7. A grating coupler, characterized in that, The grating structure is generated using the method described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, is used to implement the grating structure generation method as described in any one of claims 1 to 5.

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