Design method and device of width-graded waveguide and computer storage medium thereof

Abstract

The application discloses a design method and device of a width-graduated waveguide and a computer storage medium thereof. The width-graduated waveguide corresponding to a parameter curve is divided into N small sections with equal width intervals, the coupling efficiency of waveguide eigenmodes between each cross section of the width-graduated waveguide and the transmission efficiency of the current width-graduated waveguide are calculated, the shape of the parameter curve is adjusted while keeping the width intervals of the N small sections unchanged, the coupling efficiency between waveguide eigenmodes of each small section and between waveguide eigenmodes of two adjacent small sections which cost the most calculation time has been calculated in advance, and only the length interval of each small section updated by the changed parameter curve is assigned to each small section corresponding to the calculated waveguide eigenmode, so that the transmission efficiency of the width-graduated waveguide can be updated. The operation is simple, the calculation speed is fast, and the optimization operation of the width-graduated waveguide is greatly facilitated.

Description

Technical Field

[0001] This application relates to, but is not limited to, the field of optical integrated chips, and particularly to design methods, apparatus, and computer storage media for width-gradient waveguides. Background Technology

[0002] Tapered-width waveguides are a common structure in photonic integrated circuits, widely used for transitions between waveguides with different structures in preceding and following components. They are also applied in mode switching, couplers, and waveguide crossings. Typical tapered-width waveguides have a linearly varying width because this design is the simplest. However, to achieve low loss, linear tapered-width waveguides require relatively long lengths, which is difficult to meet in applications with strict length constraints. Therefore, nonlinear tapered-width waveguides are needed, such as hyperbolic, elliptical, and fast-insulating width variations. However, current optimization designs for nonlinear tapered-width waveguides suffer from difficulties in optimization and excessively long optimization times. Summary of the Invention

[0003] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0004] This application provides a design method, apparatus, and computer storage medium for a width-gradient waveguide, which can reduce the difficulty of optimizing the design of the width-gradient waveguide and reduce the design optimization time.

[0005] In a first aspect, embodiments of this application provide a method for designing a width-gradient waveguide, including:

[0006] Obtain the parameter curve, which corresponds to the width of the tapered waveguide changing with its length;

[0007] The tapered waveguide is divided into N segments with equal width intervals, and the coupling efficiency of each waveguide eigenmode between each cross section of the tapered waveguide is calculated.

[0008] Obtain the length intervals of the N segments corresponding to the parameter curves, assign the length intervals to each segment corresponding to the pre-calculated eigenmodes of each waveguide, and calculate the transmission efficiency of the current width-gradient waveguide.

[0009] Keeping the width interval of the N segments unchanged, modifying the shape of the parameter curve, and updating the transmission efficiency of the width-gradient waveguide.

[0010] In a second aspect, embodiments of this application provide a processing apparatus, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the width-gradient waveguide design method as described in the first aspect of this application.

[0011] Thirdly, embodiments of this application also provide a computing device, including the processing apparatus described in the second aspect of this application.

[0012] Fourthly, embodiments of this application also provide a computer-readable storage medium storing computer-executable instructions, which are used to execute the width-gradient waveguide design method of the first aspect of this application.

[0013] This application embodiment includes: dividing a width-gradient waveguide corresponding to a parameter curve into N segments with equal width intervals; calculating the waveguide eigenmodes of each segment and the coupling efficiency between the waveguide eigenmodes of two adjacent segments using eigenmode expansion; obtaining the coupling efficiency of each waveguide eigenmode between each cross-section of the width-gradient waveguide; calculating the current transmission efficiency of the width-gradient waveguide; adjusting the shape of the width-gradient waveguide by adjusting the shape of the parameter curve; during adjustment, keeping the width interval of the N segments and the preset length and width range unchanged; since the waveguide eigenmodes between the segments and the coupling efficiency between the waveguide eigenmodes of two adjacent segments, which are the most computationally time-consuming, have already been pre-calculated, it is only necessary to assign the updated length interval corresponding to each segment of the parameter curve to the pre-calculated waveguide eigenmode to update the transmission efficiency of the width-gradient waveguide. This method is simple to operate, fast to calculate, and greatly facilitates the optimization of width-gradient waveguides.

[0014] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0015] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0016] Figure 1 This is a structural view of the nonlinear width-gradient waveguide in the embodiments of this application;

[0017] Figure 2 This is a flowchart of a width-gradient waveguide design method according to an embodiment of this application;

[0018] Figure 3 This is a flowchart of a width-gradient waveguide design method according to another embodiment of this application;

[0019] Figure 4This is a flowchart of a method according to one embodiment of step 101;

[0020] Figure 5 This is a parameter curve diagram of a width-gradient waveguide design method according to an embodiment of this application;

[0021] Figure 6 yes Figure 5 The view of the width-gradient waveguide structure corresponding to the parameter curve shown;

[0022] Figure 7 yes Figure 6 The figure shows the FDTD simulation results of the tapered waveguide.

[0023] Figure 8 yes Figure 7 Comparison of FDTD simulation results for linear graded waveguides;

[0024] Figure 9 This is a parameter curve diagram of a width-gradient waveguide design method according to another embodiment of this application;

[0025] Figure 10 yes Figure 9 The view of the width-gradient waveguide structure corresponding to the parameter curve shown;

[0026] Figure 11 yes Figure 10 The figure shows the FDTD simulation results of the tapered waveguide.

[0027] Figure 12 yes Figure 11 Comparison of FDTD simulation results for linear graded waveguides;

[0028] Figure 13 This is a schematic block diagram of the processing apparatus according to the second aspect of this application;

[0029] Figure 14 This is a schematic block diagram of the computing device according to the third aspect of this application. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0031] It should be noted that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0032] Tapered-width waveguides have a wide range of applications and are currently widely used in transitions between waveguides with different structures in preceding and following components. The width of a typical tapered-width waveguide changes linearly, which is simple to calculate and easy to design. It is well known to those skilled in the art that the longer the length of a tapered-width waveguide, the easier it is to reduce its loss. Therefore, to achieve low-loss requirements, linear tapered-width waveguides are required to be relatively long. However, in some applications with strict length constraints, it is difficult to design a linearly tapered-width waveguide that meets the requirements.

[0033] Therefore, it is necessary to design nonlinear, width-gradient waveguides, for example, referencing Figure 1 As shown, the nonlinear width-gradient waveguide in this embodiment exhibits a nonlinear width variation with length. Commonly used nonlinear width-gradient waveguide designs in the art include hyperbolic, elliptical, and fast-insulating width variations. However, because the design of nonlinear width-gradient waveguides is computationally complex, repeated complex calculations are required during adjustment and optimization, leading to design difficulties and excessively long optimization times.

[0034] To address the aforementioned technical problems, embodiments of this application provide a design method, apparatus, and computer storage medium for a width-gradient waveguide, which can reduce the difficulty of optimizing the design of a width-gradient waveguide and shorten the design optimization time.

[0035] Reference Figure 2 As shown, the first aspect of this application provides a width-gradient waveguide design method according to an embodiment of this application, including but not limited to the following steps:

[0036] Step 101: Obtain the parameter curve, which corresponds to the width of the tapered waveguide changing with its length;

[0037] Step 102: Divide the tapered waveguide into N segments with equal width intervals, and calculate the coupling efficiency of each waveguide eigenmode between each cross section of the tapered waveguide.

[0038] Step 103: Obtain the length interval of the N segments corresponding to the parameter curve, assign the length interval to each segment corresponding to the pre-calculated eigenmode of each waveguide, and calculate the transmission efficiency of the current width-gradient waveguide.

[0039] Step 104: Keep the width interval of the N segments unchanged, modify the shape of the parameter curve, and update the transmission efficiency of the width-gradient waveguide.

[0040] In this embodiment, refer to Figure 5As shown, in step 101, the parameter curve is located in a length-width coordinate system, where the horizontal axis corresponds to the waveguide length and the vertical axis corresponds to the waveguide width. In this embodiment, the length units of the horizontal and vertical axes are μm. The preset length range is the length of the required width-gradient waveguide, that is, between (0, 0) and (L, 0) in the length-width coordinate system. In this embodiment, the preset width range is half the width range of the required width-gradient waveguide, for example, the preset width range of the required width-gradient waveguide is W. start To W end The aforementioned preset width range is W. start / 2 to W end / 2, which is (0, W) in the length-width coordinate system. start / 2) to (0, W) end Between / 2), the object being designed is the shape of the cross-section of the tapered waveguide along one side of the horizontal central axis. For example, in this embodiment, the object being designed is the shape of the cross-section of the tapered waveguide along the upper side of the horizontal central axis. If the shape of the tapered waveguide is symmetrical vertically along the horizontal direction, the overall shape of the tapered waveguide can be determined by determining the shape of the cross-section along one side of the horizontal direction. In this embodiment, the parameter curve represents the change in width of the tapered waveguide cross-section above the horizontal central axis as a function of length.

[0041] A parametric curve is generated within a preset length and width range in the length-width coordinate system. To facilitate control of the shape of the parametric curve, in one embodiment, curve control points are included to control its shape. The parametric curve corresponds to the width of the tapered waveguide varying with its length, and is a curve connecting the beginning and end points of the upper edge of the tapered waveguide's cross-section. In this embodiment, the coordinates of the starting point of the parametric curve in the length-width coordinate system are (0, W). start / 2), the coordinates of the termination point are (L, W) end / 2). The curve control points are points that must be established in curve control measurement to control the shape of the curve. By adjusting the coordinate position of the curve control points in the length-width coordinate system, the shape of the parametric curve can be controlled. The shape of the width-gradient waveguide can then be determined using the parametric curve. The curve control points can be set according to different curve types; one or more curve control points can be set.

[0042] In step 102 above, the width-gradient waveguide is divided into N segments with equal width intervals, where the width variation between each segment is ΔW, and N = abs(W end -W start ) / △W,W end and Wstart It is the width of the end and start points of the graded waveguide, corresponding to the aforementioned preset width range W. start / 2 to W end / 2, the width-gradient waveguide divided into N small segments is simulated numerically using eigenmode expansion (EME). When the width variation ΔW is small, each segment is considered to have a nearly constant width. The eigenmode expansion first calculates the waveguide eigenmode of each segment and the coupling efficiency between the waveguide eigenmodes of two adjacent segments.

[0043] Once the length of each segment is determined, the transmission efficiency of the overall width-gradient waveguide can be calculated. In step 103 above, the length intervals of the N segments corresponding to the parameter curve are obtained. Since the waveguide eigenmodes of each segment and the coupling efficiency between the waveguide eigenmodes of two adjacent segments have been calculated in step 102, the length intervals are assigned to the pre-calculated waveguide eigenmodes corresponding to each segment to determine the phase information of the waveguide eigenmodes. For example, the front width W of each segment is... i and the width W i+1 By interpolating this value as the independent variable into the adjusted parameter curve, the width W of each segment can be obtained. i Corresponding length position L i , and the width W i+1 Corresponding length position L i+1 The length interval of each segment is ΔL i =L i+1 -L i (i = 1, 2, ..., N). The length interval of each segment is ΔL. i By substituting the values ​​into the pre-calculated waveguide eigenmodes of each segment, the phase information of the waveguide eigenmode can be determined. Combined with the coupling efficiency of each waveguide eigenmode between each cross section, a complete transmission matrix is ​​formed, and the transmission efficiency of the current width-gradient waveguide can be quickly calculated.

[0044] To adjust the shape of the tapered waveguide in order to design the optimal tapered waveguide, in step 104 above, the shape of the parameter curve is adjusted by adjusting the coordinates of the curve control points. When the shape of the parameter curve changes, the shape of the corresponding tapered waveguide changes. In the prior art, when the shape of the tapered waveguide changes, the digital simulation of the tapered waveguide takes too much time to re-simulate and calculate. However, in this embodiment, the width interval ΔW of the N segments and the preset length range and preset width range are kept unchanged, that is, the length, starting width and ending width of the tapered waveguide are kept unchanged. The shape of the parameter curve is adjusted by changing the coordinates of the curve control points. Since the shape of the curve is controlled by the curve control points, the adjustment is very convenient and there is no need to rebuild the curve formula and formula coefficients. Since the overall starting and ending widths of the tapered waveguide remain constant, the width spacing ΔW of the N segments also remains unchanged. Changes in the shape of the parameter curve only affect the length spacing of each of the N segments. Since the waveguide eigenmodes of each segment and the coupling efficiency between adjacent segments have already been calculated in step 102, the transmission efficiency of the tapered waveguide can be quickly updated simply by assigning the changed length spacing of each segment (due to the parameter curve shape change) to the already calculated waveguide eigenmodes. i and the width W i+1 (i = 1, 2, ..., N) remain unchanged, and the width of the tapered waveguide corresponds to the parameter curve. Therefore, the front width W of each segment is... i and the width W i+1 By interpolating this value as the independent variable into the adjusted parameter curve, the width W of each segment can be obtained. i Corresponding length position L i , and the width W i+1 Corresponding length position L i+1 The length interval of each segment is ΔL i =L i+1 -L i (i = 1, 2, ..., N). The length interval of each segment is ΔL. i By substituting the values ​​into the corresponding waveguide eigenmodes of each segment, the phase information can be determined. Combined with the coupling efficiency of each waveguide eigenmode between each cross-section calculated in step 102 above, a complete transmission matrix can be constructed. This allows for rapid calculation of the coupling efficiency and the overall transmission efficiency of the tapered waveguide (the calculation time is typically within 2 seconds on a personal computer). The operation is simple and the calculation speed is fast, greatly facilitating the optimization of tapered waveguides. Due to the fast calculation speed, the shape of the curve can be easily and controllably adjusted, making it convenient to adjust the tapered waveguide and facilitating the rapid design of tapered waveguides with optimal transmission efficiency.

[0045] In another embodiment, the cross-section of the tapered waveguide can also be asymmetrical along the horizontal direction. For example, the lower side of the cross-section along the horizontal direction may be a multiple of the upper side width, such as 1 / 2, or one side of the cross-section may be a straight line while the other side has a parametric curve shape. Alternatively, the parametric curves on both sides of the horizontal central axis of the cross-section may be different. The aforementioned parametric curves can also represent the overall width of the tapered waveguide as a function of its length. For example, the cross-sectional shape of the tapered waveguide may be symmetrical along the horizontal central axis. Thus, the overall shape of the tapered waveguide can be determined by the change in its overall width as a function of its length. In this embodiment, the width range in the preset length-width coordinate system is W. start To W end The preset length range is 0 to L, and the coordinates of the starting point of the parameter curve are (0, W). start The coordinates of the termination point are (L, W) end ).

[0046] In addition, the parameter curve in the above embodiments can be a line segment that starts from the starting point and ends at the ending point. Alternatively, it can be a segment of the line shape as the parameter curve, such as a line segment between a preset length range and a preset width range in an arc as the parameter curve.

[0047] Reference Figure 3 As shown, in one embodiment of this application, the procedure further includes, but is not limited to, the following steps:

[0048] Step 105: Continuously modify the shape of the parameter curve until the transmission efficiency of the width-gradient waveguide is optimal, and obtain the corresponding preferred parameter curve.

[0049] In this embodiment, by continuously modifying the shape of the parameter curve and simulating the transmission efficiency of the width-gradient waveguide corresponding to the parameter curve shape, until the transmission efficiency is optimal, the corresponding parameter curve is the preferred parameter curve, and the width-gradient waveguide corresponding to the preferred parameter curve is the optimal width-gradient waveguide shape. In one embodiment of the present invention, the shape of the parameter curve is modified by changing the coordinates of the curve control points corresponding to the parameter curve.

[0050] If the transmission efficiency of the optimal tapered waveguide is still unsatisfactory or fails to meet design requirements, the preset overall length L of the tapered waveguide can be modified, and then the parameter curves and the corresponding transmission efficiency of the tapered waveguide can be updated. Since the waveguide eigenmodel of each segment does not need to be changed, the calculation speed is fast, and it is easy to adjust to obtain the optimal tapered waveguide shape.

[0051] Reference Figure 4As shown, in one embodiment of this application, the step 101 of obtaining the parameter curve within a preset length range and a preset width range in the length-width coordinate system includes, but is not limited to, the following steps:

[0052] Step 201: Establish a length-width coordinate system corresponding to the length and width direction of the width-gradient waveguide;

[0053] Step 202: Randomly generate a parametric curve in the length-width coordinate system, wherein the parametric curve is within a set length and width range.

[0054] In this embodiment, the coordinates of the control points of the parametric curve are randomly generated, therefore the shape of the parametric curve is also random. Of course, the system can also automatically generate a default parametric curve based on a preset width and length range.

[0055] After generating the parametric curve, the shape of the parametric curve can be changed by adjusting the coordinates of the curve control points. Since the coordinates of the curve control points are a 2D array, they can be easily adjusted. For example, the values ​​of the curve control point coordinates can be adjusted manually, or they can be adjusted by setting the system algorithm, such as automatically traversing by setting the step size of the value change.

[0056] To improve the optimization speed, in one embodiment of this application, the parameter curve is optimized by an optimization algorithm, such as particle swarm optimization (PSO) or a neural network algorithm.

[0057] Particle swarm optimization (PSO) is a population-based search process where each individual, called a particle, is defined as a potential solution to the problem in a D-dimensional search space. Each particle stores its historical best position, the best positions of all particles, and its velocity. In each generation, the particle's information is combined to adjust the velocity component in each dimension, which is then used to calculate the new particle position. Particles continuously change their states in the multidimensional search space until they reach equilibrium or an optimal state, or until computational limitations are exceeded.

[0058] In one embodiment of this application, a particle swarm optimization algorithm is used to optimize the parameter curve. First, the coordinates of the curve control points are used as random initialization particles to initialize the population and velocity. By calculating the transmission efficiency of the corresponding width-gradient waveguide, the individual extreme value and the population extreme value are found. The velocity and position of the individual are continuously updated until the termination condition is met, and the coordinates of the curve control points corresponding to the transmission efficiency of the optimal width-gradient waveguide are obtained, thereby determining the corresponding parameter curve and the shape of the width-gradient waveguide.

[0059] In another embodiment of this application, a neural network algorithm is used to optimize the parameter curves. The preset length, preset width range, and width interval of the required width-gradient waveguide are input into a trained neural network algorithm to obtain the parameter curves corresponding to the optimal transmission efficiency of the width-gradient waveguide. Training the neural network model requires constructing a training set, including multiple width-gradient waveguide length and width parameters and their corresponding parameter curves for the optimal transmission efficiency.

[0060] The particle swarm optimization algorithm and neural network algorithm mentioned above are known techniques to those skilled in the art, and will not be described in detail here.

[0061] Reference Figure 5 As shown in one embodiment of this application, the parameter curve is a Bezier curve, and the coordinates of the starting point of the parameter curve are (0, W). start / 2), the coordinates of the termination point are (L, W) end / 2). The Bézier curve includes a first curve control point A and a second curve control point B used to control the shape of the parametric curve. By adjusting the shape of the tapered waveguide using the Bézier curve and regularly moving the first and second curve control points A and B, the parametric curve will undergo a transformation similar to the stretching of a rubber band. By fine-tuning the coordinates of the first and second curve control points A and B, the shape of the parametric curve can be changed directionally, facilitating subsequent adjustments.

[0062] In one embodiment of this application, the control points of the Bézier curve are always located within a preset length range and a preset width range. This ensures that the width of the tapered waveguide is positive and does not exceed W during parametric curve optimization. end .

[0063] In other embodiments of this application, the shape of the width-gradient waveguide can also be adjusted by other parameter curves, such as using a circular arc splicing curve.

[0064] This application provides an embodiment of a width-gradient waveguide design method. The design parameters for the required width-gradient waveguide are a core layer height of 220 nm, starting from W... start =0.5μm change to W end =5μm, length L = 30μm. Correspondingly, the preset length range of the length-width coordinate system is 0 to 30μm, and the preset width range is 0.25μm to 2.5μm. Within a rectangle defined by the preset length and width ranges, a starting point with coordinates (0, W) is randomly generated. start / 2), the coordinates of the termination point are (L, W) end The cubic Bézier curve of (2) is used as the parametric curve. The Bézier curve includes two control points located at coordinates (0,0) and (0,W). end / 2),(L,W end Within the rectangle formed by the four points (L, 0) and (L, 2), the structural shape of the width-gradient waveguide is determined by the parameter curve.

[0065] Then, numerical simulation is performed using Eigenmode Expansion (EME). The tapered waveguide is preferentially divided into N small segments, with a width interval ΔW of 50 nm between two cross-sections. Therefore, dividing the tapered waveguide into 90 equally spaced segments yields 91 cross-sections with linearly varying widths. The front width W of each segment is then... i and the width W i+1 (i = 1, 2, ..., N) are the independent variables. Interpolating these values ​​into the adjusted parameter curve yields the front width W. i Corresponding length position L i , and the width W i+1 Corresponding length position L i+1 Thus, the length interval ΔL of each small segment i =L i+1 -L i (i = 1, 2, ..., N). The eigenmode expansion is used to calculate the waveguide eigenmodes of the aforementioned N segments and the coupling efficiency between the waveguide eigenmodes of two adjacent segments, thereby obtaining the coupling efficiency of each waveguide eigenmode between each cross-section of the tapered waveguide. The length intervals of the N segments corresponding to the parameter curve are obtained. Since the waveguide eigenmodes of each segment and the coupling efficiency between the waveguide eigenmodes of two adjacent segments have already been calculated, the length intervals are assigned to the pre-calculated waveguide eigenmodes corresponding to each segment to determine the phase information of the waveguide eigenmodes. Combined with the coupling efficiency of each waveguide eigenmode between each cross-section, a complete transmission matrix is ​​constructed, and the transmission efficiency of the tapered waveguide corresponding to the current parameter curve is quickly calculated. Changing the control points of the parameter curve alters its shape. Maintaining the width interval ΔW of the N segments and the preset length and width ranges unchanged, the shape change only alters the length interval ΔLi of each segment. Therefore, by assigning the length interval ΔLi to the pre-calculated waveguide eigenmodes of each segment, the transmission efficiency of the corresponding width-gradient waveguide can be quickly obtained. In this embodiment, the computation time on a personal computer is 1.3 seconds. Based on this, using a particle swarm optimization algorithm with a target fundamental mode transmission transmittance at 1550nm wavelength, the four-dimensional array consisting of the two middle control points A and B of the Bezier curve is optimized and traversed to obtain the following result: Figure 5 The preferred parameter curve shown corresponds to Figure 5 The preferred parameter curve is a width-gradient waveguide structure, such as Figure 6As shown. The graded waveguide loss verified by FDTD (Finite-Difference Time-Domain) simulation is as follows. Figure 7 As shown, the loss in the C-band is less than 0.005 dB. In contrast, if a linear, tapered waveguide is used, the FDTD simulation results for the C-band loss are between 0.11 and 0.13 dB. Figure 8 As shown, the width-gradient waveguide designed by the width-gradient waveguide design method of this application not only has a fast computation speed, but also has higher transmission efficiency and lower transmission loss than linear width-gradient waveguides of the same length.

[0066] The width-gradient waveguide designed in this embodiment can be used in various waveguide structures, such as connecting ordinary waveguides and detector structures.

[0067] Another embodiment of the width-gradient waveguide design method of this application requires the design of a variable-ridge silicon waveguide structure, with design parameters of: core layer height 220nm, from W... start =0.5μm change to W end = 8μm, length L = 100μm. Correspondingly, the preset length range of the length-width coordinate system is 0 to 100μm, and the preset width range is 0.25μm to 4μm. Within a rectangle defined by the preset length and width ranges, a starting point with coordinates (0, W) is randomly generated. start / 2), the coordinates of the termination point are (L, W) end The cubic Bézier curve of (2) is used as the parametric curve. The Bézier curve includes two control points located at coordinates (0,0) and (0,W). end / 2),(L,W end Within the rectangle formed by the four points (L, 0) and (L, 2), the structural shape of the width-gradient waveguide is determined by the parameter curve.

[0068] Then, numerical simulation is performed using Eigenmode Expansion (EME). The tapered waveguide is preferentially divided into N small segments, with a width interval ΔW of 50 nm between two cross-sections. Therefore, dividing the tapered waveguide into 150 equally spaced segments yields 151 cross-sections with linearly varying widths. The front width W of each segment is then... i and the width W i+1 (i = 1, 2, ..., N) are the independent variables. Interpolating these values ​​into the adjusted parameter curve yields the front width W. i Corresponding length position L i , and the width W i+1 Corresponding length position L i+1 Thus, the length interval ΔL of each small segmenti =L i+1 -L i (i = 1, 2, ..., N). The eigenmode expansion is used to calculate the waveguide eigenmodes of the aforementioned N segments and the coupling efficiency between the waveguide eigenmodes of two adjacent segments, thereby obtaining the coupling efficiency of each waveguide eigenmode between each cross-section of the tapered waveguide. The length intervals of the N segments corresponding to the parameter curve are obtained. Since the waveguide eigenmodes of each segment and the coupling efficiency between the waveguide eigenmodes of two adjacent segments have already been calculated, the length intervals are assigned to the pre-calculated waveguide eigenmodes corresponding to each segment to determine the phase information of the waveguide eigenmodes. Combined with the coupling efficiency of each waveguide eigenmode between each cross-section, a complete transmission matrix is ​​constructed, and the transmission efficiency of the tapered waveguide corresponding to the current parameter curve is quickly calculated. Changing the control points of the parameter curve alters its shape. Keeping the width interval ΔW of the N segments, the preset length range, and the preset width range constant, the shape change only alters the length interval ΔLi of each segment. Therefore, by assigning the length interval ΔLi to the pre-calculated waveguide eigenmode of each segment, the transmission efficiency of the corresponding width-gradient waveguide can be quickly obtained (typically within 2 seconds on a personal computer). Based on this, using a particle swarm optimization algorithm with a target fundamental mode transmission transmittance at 1550nm wavelength, the four-dimensional array consisting of the two middle control points A and B of the Bezier curve is optimized and traversed for calculation, resulting in the following... Figure 9 The preferred parameter curve shown corresponds to Figure 9 The preferred parameter curve is a width-gradient waveguide structure, such as Figure 10 As shown. The graded waveguide loss verified using FDTD simulation is as follows. Figure 11 As shown, the loss in the C-band is less than 0.002 dB. In contrast, if a linear graded waveguide is used, the FDTD simulation results for the C-band loss are between 0.06 and 0.08 dB. Figure 12 As shown, the width-gradient waveguide designed by the width-gradient waveguide design method of this application not only has a fast computation speed, but also has higher transmission efficiency and lower transmission loss than linear width-gradient waveguides of the same length.

[0069] Reference Figure 13 As shown, in one embodiment of the second aspect of this application, a processing apparatus is provided, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it executes the width-gradient waveguide design method in the above embodiment, for example, executing... Figure 2 Steps 101 to 104 shown Figure 3 Steps 101 to 105 shown Figure 4 Steps 201 to 202 are shown.

[0070] Reference Figure 14 According to one embodiment of the third aspect of this application, a computing device is provided, including as described above. Figure 13 The processing device shown is described above. The computing device can be a local computing device such as a personal computer, tablet, or mobile phone, or a cloud computing device such as a cloud server, local area network server, or cloud host.

[0071] An embodiment of the fourth aspect of this application provides a computer-readable storage medium storing computer-executable instructions that are executed by a processor or controller, for example, by... Figure 13 One of the processors can be executed, causing the processor to execute the width-gradient waveguide design method in the above embodiments, for example, executing the method described above. Figure 2 Steps 101 to 104 shown Figure 3 Steps 101 to 105 shown Figure 4 Steps 201 to 202 are shown.

[0072] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0073] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0074] The above is a detailed description of the preferred embodiments of this application. However, this application is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A method for designing a width-gradient waveguide, characterized in that, include: Obtain the parameter curve, which corresponds to the width of the tapered waveguide changing with its length; The width-gradient waveguide is divided into N segments with equal width intervals along its length direction, and the coupling efficiency of each waveguide eigenmode between each cross section of the width-gradient waveguide is calculated. Obtain the length intervals of the N segments corresponding to the parameter curves, assign the length intervals to each segment corresponding to the pre-calculated eigenmodes of each waveguide, and calculate the transmission efficiency of the current width-gradient waveguide. Keeping the width interval of the N segments unchanged, modifying the shape of the parameter curve, and updating the transmission efficiency of the width-gradient waveguide.

2. The width-gradient waveguide design method according to claim 1, characterized in that, Also includes: The shape of the parameter curve is continuously modified until the transmission efficiency of the width-gradient waveguide is optimal, thus obtaining the corresponding preferred parameter curve.

3. The width-gradient waveguide design method according to claim 1 or 2, characterized in that, Modifying the shape of the parameter curve includes: The shape of the parametric curve is modified by changing the coordinates of its control points.

4. The width-gradient waveguide design method according to claim 2, characterized in that, The continuous modification of the shape of the parameter curve includes: The shape of the parametric curve is optimized by modifying the coordinates of the curve control points using an optimization algorithm.

5. The width-gradient waveguide design method according to claim 4, characterized in that, The optimization algorithm is either particle swarm optimization or a neural network algorithm.

6. The width-gradient waveguide design method according to claim 1, characterized in that, The calculation of the coupling efficiency of each waveguide eigenmode between each cross section of the tapered waveguide includes: The coupling efficiency of each waveguide eigenmode between each cross section of the tapered waveguide is obtained by calculating the waveguide eigenmode of each segment and the coupling efficiency between the waveguide eigenmodes of two adjacent segments through eigenmode expansion.

7. The width-gradient waveguide design method according to claim 1, characterized in that, Assigning the length interval to each of the segments corresponding to the pre-calculated waveguide eigenmodes, and calculating the transmission efficiency of the current width-gradient waveguide, includes: The phase information of each waveguide eigenmode is determined by assigning the length interval to each segment corresponding to the pre-calculated waveguide eigenmode. The coupling efficiency of each waveguide eigenmode between each cross section is combined to form a complete transmission matrix, and the transmission efficiency of the current width-gradient waveguide is obtained. Updating the transmission efficiency of the width-gradient waveguide includes: The length intervals of each segment corresponding to the adjusted parameter curves are obtained. The length intervals are assigned to the pre-calculated waveguide eigenmodes corresponding to each segment to determine the phase information of each waveguide eigenmode. The coupling efficiency of each waveguide eigenmode between each cross section is combined to form a complete transmission matrix, and the transmission efficiency of the width-gradient waveguide is updated.

8. The width-gradient waveguide design method according to claim 1, characterized in that, The parameter curve is the curve connecting the first and last points on the upper edge of the cross-section of the width-gradient waveguide.

9. The method for designing a width-gradient waveguide according to claim 1, characterized in that, The parametric curve includes a starting point and an ending point, and the coordinates of the starting point are (0, ...). The coordinates of the termination point are ( ). , ), where W start The W represents the initial width of a preset gradient waveguide. end L represents the preset termination width of the gradient waveguide, and L represents the preset length range of the gradient waveguide.

10. The width-gradient waveguide design method according to claim 7, characterized in that, Obtaining the length interval of each of the aforementioned segments corresponding to the adjusted parameter curve includes: The front and back widths of each segment are interpolated into the adjusted parameter curve as independent variables to obtain two length positions corresponding to the front and back widths respectively. The difference between the two length positions is the length interval of the adjusted parameter curve corresponding to the current segment.

11. The width-gradient waveguide design method according to claim 1, characterized in that, The acquisition of parameter curves includes: Establish a length-width coordinate system corresponding to the length and width direction of the width-gradient waveguide; A parametric curve is randomly generated in the length-width coordinate system, and the parametric curve is within a set length and width range.

12. The width-gradient waveguide design method according to claim 1, 9, or 11, characterized in that, The parameter curve is a Bézier curve, and also includes two curve control points, a first curve control point and a second curve control point, for controlling the shape of the Bézier curve.

13. The width-gradient waveguide design method according to claim 11, characterized in that, The parameter curve is a Bézier curve, and also includes two first curve control points and a second curve control point for controlling the shape of the Bézier curve. The coordinates of the first curve control point and the second curve control point are within the set length range and the set width range.

14. A processing apparatus, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, when the processor executes the computer program, it implements the width-gradient waveguide design method as described in any one of claims 1 to 10.

15. A computing device, characterized in that, Includes the processing apparatus as described in claim 14.

16. A computer-readable storage medium storing computer-executable instructions for performing the width-gradient waveguide design method according to any one of claims 1 to 13.

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