Simulation method and device of mode selection coupler, equipment, storage medium and product

Abstract

The invention discloses a simulation method and device for a mode selection coupler, equipment, a storage medium and a product. The simulation method comprises the steps of constructing a side-cast single-mode fiber geometric model, a side-cast few-mode fiber geometric model and a side-cast mode selection coupler geometric model; determining a light source file based on the side-cast single-mode fiber geometric model, and determining a path monitor input mode file based on the side-cast single-mode fiber geometric model and the side-cast few-mode fiber geometric model; and performing mode selection coupler simulation according to the light source file, the path monitor input mode file and the geometric model of the side-cast mode selection coupler to obtain a simulation result. Compared with an existing mode of manually drawing a plurality of models, calculating a light source file and inputting a mode file into a path monitor for simulation, the mode provided by the invention can realize automatic operation of a simulation process, and on the premise of ensuring the calculation precision, manual operation steps are reduced, the simulation time is shortened, and the overall simulation efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of optical fiber communication technology, and in particular to simulation methods, apparatus, equipment, storage media and products for mode selection couplers. Background Technology

[0002] With the exponential growth of global data traffic, fiber optic communication systems are gradually approaching their physical capacity limits. While technologies such as Wavelength Division Multiplexing (WDM), Polarization Division Multiplexing (PDM), and higher-order modulation formats have significantly improved the transmission capacity of single-mode fiber (SMF), its Shannon limit has become a bottleneck for further capacity expansion. Space Division Multiplexing (SDM), as a key solution to overcome this bottleneck, can significantly increase the transmission capacity of fiber by introducing multiple parallel transmission channels into the fiber. Among various SDM technologies, Mode Division Multiplexing (MDM) utilizes multiple orthogonal modes in few-mode fiber (FMF) for parallel transmission, increasing transmission capacity without increasing the number of fibers. In MDM systems, the Mode (de)Multiplexer (MUX / DEMUX) is the core component, and its performance directly determines channel isolation, crosstalk level, and system bandwidth. Currently, researchers have proposed various implementation schemes for MUX / DEMUX, including free-space type (such as phase plate, spatial light modulator), integrated waveguide type (such as multimode interferometer, Y-branch), and all-fiber type, such as mode-selective coupler (MSC) and photonic lantern.

[0003] The all-fiber solution utilizes the fiber structure itself to fabricate MUX / DEMUX. Among them, the MSC with tapered side polishing structure has low insertion loss, high mechanical stability and high compatibility with fiber optic communication systems. By adjusting the geometric parameters of the two fibers to match their propagation constants, high power coupling between specific modes can be achieved. Its main design parameters include fiber core radius and cladding polishing depth. However, several problems still exist in the modeling and simulation of side-thrown MSC structures: First, although some studies use Rsoft for modeling and simulation, they often only provide the main structural parameters and simulation results, without disclosing the geometric model and specific settings in detail, which increases the difficulty of reproducibility. Second, some modeling work assumes that the cladding refractive indices of the two fibers are equal or similar, thus only establishing the core region model and assuming that the background refractive index is equal to the cladding refractive index, leading to deviations in coupling calculations. Third, when using the overlap integral method to calculate the coupling efficiency in the fiber, the input path monitor pattern file often comes from the transmission mode of an ideal circular fiber, rather than the pattern file of a D-type fiber structure with polished cladding. These simplifications may lead to deviations in simulation results, thus affecting the accuracy of the obtained optimal polishing depth and taper ratio. Fourth, the modeling process requires manipulating the input and output between multiple simulation models. When the geometric parameters of the fiber change during modeling, it is necessary to manually redraw multiple models, calculate and import light source files, calculate and import path monitor pattern files, and post-process model results, etc., which wastes simulation time. Therefore, it is necessary to study how to effectively improve the accuracy and efficiency of simulation results during the modeling process, so that they can better guide the manufacturing and optimization of actual devices. Summary of the Invention

[0004] The main objective of this application is to provide a simulation method, apparatus, device, storage medium, and product for mode selection couplers, aiming to solve the technical problem of low simulation efficiency of existing mode selection couplers.

[0005] To achieve the above objectives, this application proposes a simulation method for a mode selection coupler, the simulation method comprising: Construct geometric models of side-thrown single-mode fiber, side-thrown few-mode fiber, and side-thrown mode-selective coupler; The light source file is determined based on the side-thrown single-mode fiber geometric model, and the path monitor input mode file is determined based on the side-thrown single-mode fiber geometric model and the side-thrown few-mode fiber geometric model. The mode selection coupler was simulated based on the light source file, the path monitor input mode file, and the side-throw mode selection coupler geometry model, and the simulation results were obtained.

[0006] Optionally, the construction of the side-thrown single-mode fiber geometric model, the side-thrown few-mode fiber geometric model, and the side-thrown mode-selective coupler geometric model includes: The geometric parameters are determined according to the coupling requirements, and the geometric parameters include at least one of the following: core radius, cladding radius, grinding depth, and plane width; Generate geometric data based on the geometric parameters; Based on the geometric data, construct the geometric models of side-thrown single-mode fiber, side-thrown few-mode fiber, and side-thrown mode selection coupler.

[0007] Optionally, the simulation of the mode selection coupler based on the light source file, the path monitor input mode file, and the side-throw mode selection coupler geometry model, to obtain simulation results, includes: Batch commands are generated based on the light source file, the path monitor input mode file, and the side-projection mode selection coupler geometry model. Based on the batch processing command, a preset solver is invoked to perform beam propagation simulation and obtain simulation results.

[0008] Optionally, the step of calling a preset solver based on the batch processing command to perform beam propagation simulation and obtain simulation results includes: Based on the batch processing command, a preset solver is invoked to perform beam propagation simulation, and a first simulation result is obtained; The batch processing command is updated according to the preset simulation geometric parameters to obtain the target batch processing command; Based on the target batch processing command, the preset solver is called again to perform beam propagation simulation, a second simulation result is obtained, and the step of updating the batch processing command according to the preset simulation geometric parameters to obtain the target batch processing command is returned, until all the preset simulation geometric parameters are traversed.

[0009] Optionally, the step of calling a preset solver based on the batch processing command to perform beam propagation simulation and obtain simulation results includes: Parametric scanning was performed on the residual cladding thickness and wavelength to obtain the scanning results; Based on the scanning results, determine whether the residual cladding thickness and the wavelength have changed; If the residual cladding thickness and the wavelength change, return to the steps of constructing the geometric model of the side-thrown single-mode fiber, the geometric model of the side-thrown few-mode fiber, and the geometric model of the side-thrown mode selection coupler.

[0010] Optionally, the simulation of the mode selection coupler based on the light source file, the path monitor input mode file, and the side-throw mode selection coupler geometry model, to obtain simulation results, includes: The simulation results are analyzed to obtain the analytical results; The coupling efficiency at different residual cladding thicknesses and wavelengths is determined based on the analytical results.

[0011] Furthermore, to achieve the above objectives, this application also proposes a simulation device for a mode selection coupler, the simulation device for the mode selection coupler comprising: The geometry model building module is used to build geometric models of side-thrown single-mode fiber, side-thrown few-mode fiber, and side-thrown mode selection coupler. The determination module is used to determine the light source file based on the side-thrown single-mode fiber geometric model, and to determine the path monitor input mode file based on the side-thrown single-mode fiber geometric model and the side-thrown few-mode fiber geometric model. The simulation module is used to perform mode selection coupler simulation based on the light source file, the path monitor input mode file, and the side-throw mode selection coupler geometry model, and obtain simulation results.

[0012] Furthermore, to achieve the above objectives, this application also proposes a simulation device for a mode selection coupler, the device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the simulation method for the mode selection coupler as described above.

[0013] In addition, to achieve the above objectives, this application also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the simulation method for the mode selection coupler as described above.

[0014] In addition, to achieve the above objectives, this application also provides a computer program product, which includes a computer program that, when executed by a processor, implements the steps of the simulation method for the mode selection coupler as described above.

[0015] This application constructs a side-thrown single-mode fiber geometric model, a side-thrown few-mode fiber geometric model, and a side-thrown mode selection coupler geometric model. Based on the side-thrown single-mode fiber geometric model, a light source file is determined; based on the side-thrown single-mode fiber geometric model and the side-thrown few-mode fiber geometric model, a path monitor input mode file is determined. Mode selection coupler simulation is performed based on the constructed side-thrown single-mode fiber geometric model and the side-thrown few-mode fiber geometric model, and the mode selection coupler simulation is performed in conjunction with the constructed side-thrown mode selection coupler geometric model. Compared to the existing method of manually drawing multiple models and calculating the light source file and path monitor input mode file, the above method of this application can automate the simulation process, reduce manual operation steps, shorten simulation time, and improve overall simulation efficiency while ensuring calculation accuracy. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating the simulation method for selecting a coupler for the mode of this application is provided in Embodiment 1. Figure 2 A flowchart illustrating the simulation method for selecting a coupler for the mode of this application, provided in Embodiment 2; Figure 3 A diagram of a semi-coupler based on a quartz substrate with a side-polished structure is provided in Embodiment 2 of the simulation method for selecting a coupler for the mode of this application. Figure 4 A schematic diagram of an MSC based on a side polishing structure is provided in Embodiment 2 of the simulation method for selecting a coupler for the mode of this application. Figure 5 The simulation method for selecting the coupler for this application, as provided in Embodiment 2, shows the transmission cross-section model of the MSC in Rsoft. Figure 6 The flowchart of the MATLAB and Rsoft joint automated simulation provided in Embodiment 2 of the simulation method for selecting couplers for the mode of this application; Figure 7The simulation method for selecting a coupler for the mode of this application, embodiment two, provides stable transmission mode files for D-type and circular SMF structures; Figure 8 The simulation method for selecting a coupler for the mode of this application, embodiment two, provides an input editing block diagram of the light source in Rsoft; Figure 9 The feature value editing table diagram in Rsoft provided in Embodiment 2 of the simulation method for selecting couplers for the mode of this application; Figure 10 The path monitor editing block diagram in Rsoft provided in Embodiment 2 of the simulation method for selecting couplers for the mode of this application; Figure 11 The simulation method for selecting couplers for the mode of this application, as provided in Embodiment 2, includes D-type and circular FMF structures with LP. 12 Schematic file diagram; Figure 12 A comparison of the transmission curve coupling results of D-type and circular input optical field and path monitor mode files provided in Embodiment 2 of the simulation method for selecting couplers for the mode of this application; Figure 13 The simulation method for selecting a coupler for the mode of this application, as provided in Embodiment 2, provides the LP 12 The relationship between coupling efficiency and coupling length of the mode MSC and the RCT of the SMF; Figure 14 The simulation method for selecting a coupler for the mode of this application, as provided in Embodiment 2, provides the LP 12 The relationship between coupling efficiency and coupling length of the mode MSC and the incident wavelength; Figure 15 A schematic diagram of the module structure of the simulation device for the mode selection coupler in the embodiments of this application; Figure 16 This is a schematic diagram of the hardware operating environment involved in the simulation method of the mode selection coupler in the embodiments of this application.

[0019] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0021] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0022] The main solution of this application embodiment is as follows: Constructing a side-thrown single-mode fiber geometric model, a side-thrown few-mode fiber geometric model, and a side-thrown mode selection coupler geometric model; determining the light source file based on the side-thrown single-mode fiber geometric model; determining the path monitor input mode file based on the side-thrown single-mode fiber geometric model and the side-thrown few-mode fiber geometric model; performing mode selection coupler simulation based on the light source file, the path monitor input mode file, and the side-thrown mode selection coupler geometric model to obtain simulation results. Since this application determines the light source file and path monitor input mode file based on the constructed side-thrown single-mode fiber geometric model and the side-thrown few-mode fiber geometric model, and performs mode selection coupler simulation in conjunction with the constructed side-thrown mode selection coupler geometric model, compared to the existing method of manually drawing multiple models and calculating the light source file and path monitor input mode file, the above method of this application can automate the simulation process, reduce manual operation steps, reduce simulation time, and improve overall simulation efficiency while ensuring calculation accuracy.

[0023] It should be noted that the executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, or mobile phone, or an electronic device or a simulation device for a mode selection coupler capable of performing the above functions. The following description uses a simulation device for a mode selection coupler as an example to illustrate this embodiment and the subsequent embodiments.

[0024] Based on this, embodiments of this application provide a simulation method for a mode selection coupler, referring to... Figure 1 , Figure 1 A flowchart illustrating the simulation method for selecting a coupler for the mode of this application is provided in Embodiment 1.

[0025] In this embodiment, the simulation method for the mode selection coupler includes the following steps: Step S10: Construct the geometric model of the side-thrown single-mode fiber, the geometric model of the side-thrown few-mode fiber, and the geometric model of the side-thrown mode selection coupler; It should be noted that the construction of the side-thrown single-mode fiber geometric model, the side-thrown few-mode fiber geometric model, and the side-thrown mode selection coupler geometric model can be achieved by writing a custom coordinate script in MATLAB and importing the generated geometric data into Rsoft software to construct the D-type SMF structure, the D-type FMF structure, and the D-type side-coupled structure of the MSC, i.e., the side-thrown single-mode fiber geometric model, the side-thrown few-mode fiber geometric model, and the side-thrown mode selection coupler geometric model. The D-type fiber can be replaced with elliptical cladding fiber or asymmetric grooved fiber, as long as it possesses lateral energy leakage characteristics and can achieve mode coupling. MATLAB is a mathematical software and programming environment that integrates algorithm development, numerical calculation, data visualization, and engineering drawing functions. It is used to generate the geometric contour coordinates and material distribution data of the device according to specified rules, i.e., the custom coordinate script. For example, parameterized variables such as the cross-sectional boundary points of the D-type fiber, the polygon vertices of the inner and outer cladding and core, the grinding depth, and the gap, and output them as text or in a format recognizable by RSoft. Its core value lies in decoupling design parameters from geometry, facilitating parameter scanning and optimization, and integrating with subsequent simulation, visualization, and manufacturing processes. The specified rules can include predefined geometric parameters such as grinding depth d, gap g, coupling length L, and core / cladding refractive index. The Rsoft software is a photonics simulation and design suite covering device to system design and analysis, with core capabilities including waveguide and device simulation based on beam propagation method (BPM). All structures established in the above steps include a core portion and a D-type cladding portion with a specific grinding depth, realistically reflecting the geometric morphology and optical field distribution characteristics of actual devices.

[0026] Furthermore, step S10 may include: determining geometric parameters according to coupling requirements, wherein the geometric parameters include at least one of the following: core radius, cladding radius, grinding depth, and plane width; Generate geometric data based on the geometric parameters; Based on the geometric data, construct the geometric models of side-thrown single-mode fiber, side-thrown few-mode fiber, and side-thrown mode selection coupler.

[0027] It should be noted that the coupling requirements can refer to the requirements of the side-projection mode selection coupler (D-type MSC) in terms of optical performance, process feasibility, and application scenarios. For example, if the requirement is high coupling efficiency and short coupling length, a larger evanescent field is needed, requiring a larger grinding depth (within the allowable range of the process); if the requirement is low loss and high stability, a moderate grinding depth is needed to avoid excessively weakening the mechanical strength of the cladding; if the requirement is high mode selectivity, it is necessary to match the specific mode field distributions of the SMF and FMF, which may require fine-tuning the core radius and grinding depth to change the mode size and overlap. The generation of geometric data based on the geometric parameters can be achieved using MATLAB.

[0028] Step S20: Determine the light source file based on the side-thrown single-mode fiber geometric model, and determine the path monitor input mode file based on the side-thrown single-mode fiber geometric model and the side-thrown few-mode fiber geometric model; It should be noted that the light source file can be the spatial distribution of the incident light field. In the simulation, it is used as the excitation source to define the initial field shape of the light at the device entrance. In this embodiment, the light source file is obtained based on the side-thrown single-mode fiber geometric model. The path monitor input mode file can be the mode field distribution used by the monitor to "identify / project" it, including two path monitor input mode files determined based on the side-thrown single-mode fiber geometric model and the side-thrown few-mode fiber geometric model.

[0029] Step S30: Perform simulation of the mode selection coupler based on the light source file, the path monitor input mode file, and the side-throw mode selection coupler geometric model to obtain simulation results.

[0030] It should be noted that the simulation results may include: monitor power files, field distribution files, log files, etc. The simulation of the mode selection coupler based on the light source file, the path monitor input mode file, and the side-thrown mode selection coupler geometry model yields simulation results by using the transmission mode calculated from the D-type SMF structure (i.e., the side-thrown single-mode fiber geometry model) as the MSC's light source file, and simultaneously using the transmission modes calculated from the D-type SMF structure and the D-type FMF structure (i.e., the side-thrown few-mode fiber geometry model) as the path monitor's input mode files. Based on this, the coupling efficiency and coupling length of the established structure are calculated using the overlap integral method, thereby making the design parameters more closely match the physical characteristics of the actual side-thrown MSC and improving the accuracy and reliability of the simulation results. This embodiment, through the collaborative work of MATLAB and Rsoft, automates the simulation process, reducing manual operation steps, shortening simulation time, and improving overall simulation efficiency while ensuring computational accuracy.

[0031] This embodiment also includes: analyzing the simulation results to obtain analytical results; The coupling efficiency at different residual cladding thicknesses and wavelengths is determined based on the analytical results.

[0032] It should be noted that analyzing the simulation results can be done by using MATLAB (or other tools) to read the simulation result file, perform data processing and calculations, and extract the performance indicators of interest. Then, based on the extracted performance indicators, the residual cladding thickness (obtained from different grinding depths), wavelength, and coupling efficiency, etc., can be determined.

[0033] This embodiment constructs a side-thrown single-mode fiber geometric model, a side-thrown few-mode fiber geometric model, and a side-thrown mode selection coupler geometric model. Based on the side-thrown single-mode fiber geometric model, a light source file is determined. Based on the side-thrown single-mode fiber geometric model and the side-thrown few-mode fiber geometric model, a path monitor input mode file is determined. Mode selection coupler simulation is performed based on the light source file, the path monitor input mode file, and the side-thrown mode selection coupler geometric model to obtain simulation results. Since this embodiment determines the light source file and path monitor input mode file based on the constructed side-thrown single-mode fiber geometric model and the side-thrown few-mode fiber geometric model, and performs mode selection coupler simulation in conjunction with the constructed side-thrown mode selection coupler geometric model, compared to the existing method of manually drawing multiple models and calculating the light source file and path monitor input mode file, this embodiment automates the simulation process, reduces manual operation steps, lowers simulation time, and improves overall simulation efficiency while ensuring calculation accuracy.

[0034] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in the first embodiment described above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 2 , Figure 2 The flowchart provided in Embodiment 2 of the simulation method for selecting a coupler for the mode of this application includes the following steps in step S30: Step S301: Generate batch processing commands based on the light source file, the path monitor input mode file, and the side-projection mode selection coupler geometry model; It should be noted that in this embodiment, a .bat script is written in MATLAB to call the Rsoft bsimw32 solver to perform beam propagation simulation. The batch processing command can be the .bat script generated based on the parameter combination corresponding to the light source file, the path monitor input mode file, and the side-projection mode selection coupler geometry model.

[0035] Step S302: Based on the batch processing command, call the preset solver to perform beam propagation simulation and obtain the simulation results.

[0036] It should be noted that the preset solver can be Rsoft's bsimw32 solver. During the simulation, automatic control of modeling and solving under different geometric parameters can be achieved by writing .bat files.

[0037] Furthermore, in order to achieve simulation of different geometric parameters, step S202 may include: calling a preset solver based on the batch processing command to perform beam propagation simulation and obtain a first simulation result; The batch processing command is updated according to the preset simulation geometric parameters to obtain the target batch processing command; Based on the target batch processing command, the preset solver is called again to perform beam propagation simulation, a second simulation result is obtained, and the step of updating the batch processing command according to the preset simulation geometric parameters to obtain the target batch processing command is returned, until all the preset simulation geometric parameters are traversed.

[0038] It should be noted that the above description in this embodiment is a cyclical iterative batch simulation process: first, a simulation is executed (using an initial batch processing command) to obtain the simulation results; then, the batch processing command is updated sequentially according to the preset geometric parameter list, and the simulation is repeated, and the update is repeated, until all parameter combinations have been completed. The preset simulation geometric parameters can be a set of parameters (e.g., grinding depth [5, 8, 10, 12] μm, gap [10, 15, 20] μm, coupling length range, etc.), which enumerates all possible combinations in the design space or samples at a certain step size.

[0039] Once the residual cladding thickness and wavelength of the MSC change, the light source file and the monitor mode files in both paths need to be regenerated. Therefore, step S202 may include: performing a parametric scan on the residual cladding thickness and wavelength to obtain the scan results. Based on the scanning results, determine whether the residual cladding thickness and the wavelength have changed; If the residual cladding thickness and the wavelength change, return to the steps of constructing the geometric model of the side-thrown single-mode fiber, the geometric model of the side-thrown few-mode fiber, and the geometric model of the side-thrown mode selection coupler.

[0040] It should be noted that, in this embodiment, the residual cladding thickness and wavelength are parametrically scanned before simulation. Once the residual cladding thickness and wavelength of the MSC change, the light source file and the monitor mode files in both paths need to be regenerated.

[0041] In practice, Figure 3Example 2 of the simulation method for selecting couplers in this application provides a semi-coupler diagram based on a quartz substrate and featuring a side-polished structure. The marked area in the middle section represents the area requiring polishing during actual fabrication. After polishing the fiber cladding, the polished portions of the two semi-couplers are precisely joined and coupled to form an MSC. Based on this polishing structure, a [further details about the design and implementation are needed]. Figure 4 The simulation model. Figure 4 This is a schematic diagram of an MSC based on a side-polished structure, provided in Embodiment 2 of the simulation method for mode selection couplers in this application. In the model, the upper blue section represents the SMF (Self-Modified Fiber), and the lower green section represents the FMF (Fiber-Modified Fiber). The two fibers are closely arranged. The Residual Cladding Thickness (RCT) represents the remaining cladding thickness after tapering and polishing. In the simulation, a light source is input from one end of the SMF, and energy exchange occurs within the coupling region of the two fibers. When the propagation constant of the guided mode in the SMF matches the propagation constant of a certain mode in the FMF, mode coupling can be achieved through evanescent field interaction, thereby exciting higher-order modes in the FMF. Based on... Figure 4 The coupling region was used to build an MSC model in Rsoft. Figure 5 The simulation method for selecting the coupler for this application provides a transmission cross-section model diagram of the MSC in Rsoft. Figure 5 This is a cross-sectional view of the transmission direction of the model built for the LP12 mode of FMF. The left side shows the core and cladding of SMF, with a taper ratio (the ratio of the front and rear radii of the fiber) of 1.24. The right side shows the core and cladding of FMF with a multi-ring core trench-assisted structure, with a taper ratio of 1. The marked parts in the figure represent the fiber core, corresponding to the two monitoring paths. The vertical distances of the two cores from the edge of the D-shape correspond to... Figure 4 The RCT in the model. This embodiment performs simulation based on this model, and the overall simulation flowchart is as follows. Figure 6 As shown, an automated simulation process for a D-type side-launched MSC was implemented using collaborative control based on MATLAB and Rsoft. The entire simulation process includes the model building stage and the post-processing stage.

[0042] 1. Model Building Phase First, based on the matching results of the effective refractive index of the mode calculated in the multiphysics numerical simulation platform (COMSOL), when the taper ratio of the SMF is 1.24 and RCT1 is 1.2 μm, its propagation constant matches the propagation constant of the LP12 mode in the FMF with RCT2 of 0 μm. MATLAB generates a D-type fiber geometry coordinate file for the LP12 mode based on this matching result, and imports it into Rsoft to construct D-type SMF, FMF, and MSC structural models at a set wavelength. Subsequently, a .bat script was written in MATLAB to call the grmod solver in Rsoft. The command for the SMF script was `grmod %s wait=0 prefix=mode free_space_wavelength=1.55 RCT=1.2 T_SMF=1.24\n`, where `free_space_wavelength` is the incident wavelength of 1.55 μm, `RCT` is the residual cladding thickness of the SMF, and `T_SMF` is the taper ratio. The command for the FMF script was `grmod %s wait=0 prefix=mode free_space_wavelength=1.55 RCT=0 T=1\n`, generating stable transmission mode files for both D-type SMF and FMF. The stable mode file output by the SMF was used as the initial optical field input file for the MSC, referring to... Figure 7 , Figure 7 The simulation method for selecting a coupler for this application provides stable transmission mode files for D-type and circular SMF structures in Embodiment 2. Figure 7 Comparison images of the D-type light field file (a) and the circular light field file (b) clearly show that the energy center of the D-type light field has shifted, deviating towards the opposite direction of the polishing process and exhibiting an elliptical distribution, which is closer to the actual light field characteristics in a side-polishing structure. (Refer to...) Figure 8 , Figure 8 The simulation method for selecting a coupler for the mode of this application, as provided in Embodiment 2, includes an input editing block diagram of the light source in Rsoft. Figure 8 In the Launch Parameters module of Rsoft software, you can write commands in a .bat script to use the output pattern file of SMF as input to the Input File Spec. Simply prefix the pattern file name with a '$' symbol and add the pattern file name to the feature value editing table. (See reference...) Figure 9 , Figure 9 The feature value editing table diagram in Rsoft provided in Embodiment 2 of the simulation method for selecting couplers for the mode of this application; Figure 9 The SMFpathfile in the file is the name of the light field mode file that needs to be imported.

[0043] Figure 9The Symbol Table Eidor, built for the Rsoft software, contains the following feature parameters: MSC length (30000µm), circular radii R1, R2, R3, R4, R5, R6, and R7 of the multi-ring core trench-assisted FMF, residual cladding thickness RCT1 and RCT2 of the SMF, cladding radius R_clad of the SMF, core radius R_core, taper ratio T_SMF of the SMF, and taper ratio T of the FMF. The feature values ​​can be edited within the Symbol Table.

[0044] During the establishment of the MSC model, the output mode file of the D-type SMF is used as the monitor mode file in path 1, that is... Figure 9 The SMFpathfile in path 2 uses the FMF output mode file as the monitor mode file. Figure 9 The FMFpathfile in the file. Figure 10 The Pathway Monitors module in Rsoft software, like the input edit box for light sources, requires a $ sign before the file name to enable automated script import.

[0045] Reference Figure 11 , Figure 11 The simulation method for selecting couplers in this application, as described in Embodiment 2, provides LP12 mode file diagrams for D-type and circular FMF structures. It can be seen that the circular FMF exhibits stronger mode symmetry, while the D-type structure shows asymmetry in mode distribution. Rsoft calculates the coupling efficiency during transmission using the overlap integral method based on the input mode file in the path. Let the transmitted optical field in the fiber be... The input path monitor mode file is The coupling efficiency is then defined as:

[0046] In the formula, For coupling efficiency, The result is a complex conjugate. A .bat script was then written in MATLAB to call the Rsoft bsimw32 solver for beam propagation simulation. The script command is: `bsimw32 %s wait=0 prefix=result free_space_wavelength=1.55 RCT1=1.2 SMFpathfile= mode_avg_mode.m00 FMFpathfile=index_distributionXY_R7.m09\n`. During the simulation, automatic control of modeling and solving under different geometric parameters can be achieved by writing .bat files.

[0047] 2. Post-processing stage After the model calculation is completed, the post-processing stage begins. This stage requires parameterized scanning of the residual cladding thickness and wavelength. It is important to note that if the residual cladding thickness and wavelength of the MSC change, the light source file and the monitor pattern files for both paths must be regenerated. Therefore, the steps in the first model building stage need to be repeated, including regenerating the D-type fiber coordinates, model structure, and pattern files as light source and path monitor pattern files under the new parameters. To improve efficiency, this embodiment uses a MATLAB script to automatically iterate and calculate key performance indicators such as coupling efficiency and coupling length. The final output includes coupling efficiency curves for different residual cladding thicknesses and wavelengths.

[0048] Reference Figure 12 , Figure 12 Comparison of transmission curve coupling results for D-type and circular input light field and path monitor mode files provided in Embodiment 2 of the simulation method for selecting couplers for the mode of this application. Figure 12 A comparison of the transmission curves and coupling efficiencies when using D-type and circular mode files as inputs reveals that periodic coupling is achieved in both the SMF and FMF, and the fundamental mode in the SMF successfully excites higher-order modes in the FMF. The results demonstrate that the modeling parameters and simulation method in this embodiment possess good accuracy and reliability. Specifically, the transmission curve of the D-type structure is smoother, with a maximum coupling efficiency exceeding 90%, while the transmission curve of the circular structure exhibits more fluctuations and a relatively lower coupling efficiency.

[0049] Figure 13 and Figure 14 The result of parametric scanning, Figure 13 The curves show the coupling efficiency and coupling length of the MSC as a function of the RCT of the SMF. When the RCT is small (0~1.2µm), the coupling efficiency is high, reaching over 90%. As the RCT increases, the coupling efficiency decreases rapidly. When the RCT reaches 5µm, the coupling efficiency is only about 15%. When the RCT increases, the optical field overlap area decreases and the mode coupling strength weakens. Therefore, a longer propagation distance is required to complete energy exchange. All of these indicate that the coupling performance is extremely sensitive to the geometric parameters of the D-type fiber. Figure 14 The study examines the mode coupling performance within the C-band (1530~1565nm) as a function of wavelength. It shows that the coupling efficiency decreases slightly with increasing wavelength, while the coupling length remains relatively stable, exhibiting minimal overall fluctuation. This result demonstrates that the D-type side-thrown MSC designed in this embodiment possesses good tolerance characteristics to the operating wavelength and can achieve stable mode coupling performance over a wide wavelength range, thus meeting the application requirements for multi-wavelength signal transmission.

[0050] Except LP 01 LP 12 In addition to this mode, this embodiment can also be extended to other higher-order modes (LP). 21 LP 02 Coupled studies of wavelengths (e.g., S, L, or O bands) are also possible. The wavelength can also be extended to MSC designs in different operating bands (e.g., S, L, or O bands). MATLAB can be replaced with Python or LabVIEW, and Rsoft can be controlled via command line to achieve the same automated simulation process.

[0051] This embodiment generates batch commands based on the light source file, the path monitor input mode file, and the side-projection mode selection coupler geometry model. Based on these batch commands, a preset solver is invoked to perform beam propagation simulation, yielding simulation results. This embodiment also utilizes a .bat script written in MATLAB to automatically iterate and calculate, obtaining the simulation results. This approach reduces manual steps, lowers simulation time, and improves overall simulation efficiency while maintaining computational accuracy.

[0052] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the simulation method of the mode selection coupler of this application. Any simple transformations based on this technical concept are within the protection scope of this application.

[0053] This application also provides a simulation device for a mode selection coupler; please refer to [reference needed]. Figure 15 The simulation device for the mode selection coupler includes: The geometric model construction module 10 is used to construct the geometric model of the side-thrown single-mode fiber, the geometric model of the side-thrown few-mode fiber, and the geometric model of the side-thrown mode selection coupler. The determination module 20 is used to determine the light source file based on the side-thrown single-mode fiber geometric model, and to determine the path monitor input mode file based on the side-thrown single-mode fiber geometric model and the side-thrown few-mode fiber geometric model. Simulation module 30 is used to perform mode selection coupler simulation based on the light source file, the path monitor input mode file, and the side-throw mode selection coupler geometry model, and obtain simulation results. This embodiment constructs a side-throw single-mode fiber geometry model, a side-throw few-mode fiber geometry model, and a side-throw mode selection coupler geometry model; determines the light source file based on the side-throw single-mode fiber geometry model; determines the path monitor input mode file based on the side-throw single-mode fiber geometry model and the side-throw few-mode fiber geometry model; and performs mode selection coupler simulation based on the light source file, the path monitor input mode file, and the side-throw mode selection coupler geometry model to obtain simulation results. Since this embodiment determines the light source file and path monitor input mode file based on the constructed side-throw single-mode fiber geometry model and the side-throw few-mode fiber geometry model, and combines this with the constructed side-throw mode selection coupler geometry model for mode selection coupler simulation, compared to the existing method of manually drawing multiple models and calculating the light source file and path monitor input mode file, this embodiment automates the simulation process, reduces manual operation steps, lowers simulation time, and improves overall simulation efficiency while ensuring calculation accuracy.

[0054] The simulation apparatus for mode selection couplers provided in this application employs the simulation method for mode selection couplers described in the above embodiments, which can solve the technical problem of low simulation efficiency of existing mode selection couplers. Compared with the prior art, the beneficial effects of the simulation apparatus for mode selection couplers provided in this application are the same as those of the simulation method for mode selection couplers provided in the above embodiments, and other technical features in the simulation apparatus for mode selection couplers are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0055] This application provides a simulation device for a mode selection coupler. The simulation device for the mode selection coupler includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the simulation method for the mode selection coupler in the first embodiment described above.

[0056] The following is for reference. Figure 16The diagram illustrates a structural schematic of a simulation device suitable for implementing the mode selection coupler in the embodiments of this application. The simulation device for the mode selection coupler in the embodiments of this application may include, but is not limited to, mobile terminals such as mobile phones, laptops, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Description), PMPs (Portable Media Players), in-vehicle terminals (e.g., in-vehicle navigation terminals), and fixed terminals such as digital TVs and desktop computers. Figure 16 The simulation device of the mode selection coupler shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0057] like Figure 16 As shown, the emulation device of the mode selection coupler may include a processing unit 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in read-only memory (ROM) 1002 or a program loaded from storage device 1003 into random access memory (RAM) 1004. The RAM 1004 also stores various programs and data required for the operation of the emulation device of the mode selection coupler. The processing unit 1001, ROM 1002, and RAM 1004 are interconnected via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to the I / O interface 1006: input devices 1007 including, for example, touch screens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices 1008 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 1003 including, for example, magnetic tapes, hard disks, etc.; and communication devices 1009. Communication device 1009 allows the simulation device of the mode selection coupler to communicate wirelessly or wiredly with other devices to exchange data. Although the figure shows a simulation device with various systems for the mode selection coupler, it should be understood that implementation or having all of the systems shown is not required. More or fewer systems may be implemented alternatively.

[0058] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 1003, or installed from ROM 1002. When the computer program is executed by processing device 1001, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0059] The simulation device for mode selection couplers provided in this application employs the simulation method for mode selection couplers described in the above embodiments, which can solve the technical problem of low simulation efficiency of existing mode selection couplers. Compared with the prior art, the beneficial effects of the simulation device for mode selection couplers provided in this application are the same as those of the simulation method for mode selection couplers provided in the above embodiments, and other technical features in the simulation device for mode selection couplers are the same as those disclosed in the previous embodiment method, and will not be repeated here.

[0060] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0061] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0062] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the simulation method of the mode selection coupler in the above embodiments.

[0063] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0064] The aforementioned computer-readable storage medium may be included in the simulation device of the mode selection coupler; or it may exist independently and not assembled into the simulation device of the mode selection coupler.

[0065] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof. These programming languages ​​include object-oriented programming languages—such as Python, Java, Smalltalk, and C++—and conventional procedural programming languages—such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0066] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0067] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0068] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the simulation method of the above-described mode selection coupler, which can solve the technical problem of low simulation efficiency of existing mode selection couplers. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as the beneficial effects of the simulation method of the mode selection coupler provided in the above embodiments, and will not be repeated here.

[0069] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the simulation method for the mode selection coupler as described above.

[0070] The computer program product provided in this application can solve the technical problem of low simulation efficiency of existing mode selection couplers. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as those of the simulation method for mode selection couplers provided in the above embodiments, and will not be repeated here.

[0071] The above description is only a part of the embodiments of this application and does not limit the scope of protection of this application. All equivalent structural transformations made under the technical concept of this application and using the content of this application specification and drawings, or direct / indirect applications in other related technical fields, are included in the scope of protection of this application.

Claims

1. A simulation method for a mode selection coupler, characterized in that, The simulation method for the mode selection coupler includes the following steps: Construct geometric models of side-thrown single-mode fiber, side-thrown few-mode fiber, and side-thrown mode-selective coupler; The light source file is determined based on the side-thrown single-mode fiber geometric model, and the path monitor input mode file is determined based on the side-thrown single-mode fiber geometric model and the side-thrown few-mode fiber geometric model. The mode selection coupler was simulated based on the light source file, the path monitor input mode file, and the side-throw mode selection coupler geometry model, and the simulation results were obtained.

2. The simulation method for the mode selection coupler as described in claim 1, characterized in that, The construction of the side-thrown single-mode fiber geometric model, the side-thrown few-mode fiber geometric model, and the side-thrown mode-selective coupler geometric model includes: The geometric parameters are determined according to the coupling requirements, and the geometric parameters include at least one of the following: core radius, cladding radius, grinding depth, and plane width; Generate geometric data based on the geometric parameters; Based on the geometric data, construct the geometric models of side-thrown single-mode fiber, side-thrown few-mode fiber, and side-thrown mode selection coupler.

3. The simulation method for the mode selection coupler as described in claim 1, characterized in that, The simulation of the mode selection coupler is performed based on the light source file, the path monitor input mode file, and the side-throw mode selection coupler geometry model, and the simulation results are obtained, including: Batch commands are generated based on the light source file, the path monitor input mode file, and the side-projection mode selection coupler geometry model. Based on the batch processing command, a preset solver is invoked to perform beam propagation simulation and obtain simulation results.

4. The simulation method for the mode selection coupler as described in claim 3, characterized in that, The step of calling a preset solver based on the batch processing command to perform beam propagation simulation and obtaining simulation results includes: Based on the batch processing command, a preset solver is invoked to perform beam propagation simulation, and a first simulation result is obtained; The batch processing command is updated according to the preset simulation geometric parameters to obtain the target batch processing command; Based on the target batch processing command, the preset solver is called again to perform beam propagation simulation, a second simulation result is obtained, and the step of updating the batch processing command according to the preset simulation geometric parameters to obtain the target batch processing command is returned, until all the preset simulation geometric parameters are traversed.

5. The simulation method for the mode selection coupler as described in claim 3, characterized in that, The step of calling a preset solver based on the batch processing command to perform beam propagation simulation and obtaining simulation results includes: Parametric scanning was performed on the residual cladding thickness and wavelength to obtain the scanning results; Based on the scanning results, determine whether the residual cladding thickness and the wavelength have changed; If the residual cladding thickness and the wavelength change, return to the steps of constructing the geometric model of the side-thrown single-mode fiber, the geometric model of the side-thrown few-mode fiber, and the geometric model of the side-thrown mode selection coupler.

6. The simulation method for the mode selection coupler as described in any one of claims 1-4, characterized in that, The simulation of the mode selection coupler is performed based on the light source file, the path monitor input mode file, and the side-throw mode selection coupler geometry model, and the simulation results are obtained, including: The simulation results are analyzed to obtain the analytical results; The coupling efficiency at different residual cladding thicknesses and wavelengths is determined based on the analytical results.

7. A simulation device for a mode selection coupler, characterized in that, The simulation device for the mode selection coupler includes: The geometry model building module is used to build geometric models of side-thrown single-mode fiber, side-thrown few-mode fiber, and side-thrown mode selection coupler. The determination module is used to determine the light source file based on the side-thrown single-mode fiber geometric model, and to determine the path monitor input mode file based on the side-thrown single-mode fiber geometric model and the side-thrown few-mode fiber geometric model. The simulation module is used to perform mode selection coupler simulation based on the light source file, the path monitor input mode file, and the side-throw mode selection coupler geometry model, and obtain simulation results.

8. A simulation device for a mode selection coupler, characterized in that, The device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the simulation method for the mode selection coupler as described in any one of claims 1 to 6.

9. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the simulation method for the mode selection coupler as described in any one of claims 1 to 6.

10. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the steps of the simulation method for the mode selection coupler as described in any one of claims 1 to 6.

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