Optimization method of multimode crossed waveguide, waveguide, optical device and terminal

Abstract

The invention particularly relates to an optimization method of a multimode crossed waveguide, a waveguide, an optical device and a terminal. The optimization method comprises the following steps: S10, generating a control point set according to model parameters of the crossed waveguide; s20, taking the model parameters and the control point set as input, and obtaining a loss value through a loss prediction model; s30, optimizing the control point set through a spline curve function, taking the optimized control point set as an iteration variable, and iteratively executing the step S20; and S40, when the loss value is minimum, stopping iterative operation, and outputting the control point set corresponding to the minimum loss value. According to the method, the structural design of the crossed waveguide is presented in a control point set mode, and meanwhile, on the basis of model parameters, crosstalk of the crossed waveguide is reduced through optimization of the control point set, so that the purposes of reducing design difficulty of the crossed waveguide and reducing insertion loss and crosstalk of the crossed waveguide are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of crossed waveguides, and in particular to an optimization method, a waveguide, an optical device and a terminal of a multimode crossed waveguide. Background Art

[0002] With the rapid development of on-chip integrated optoelectronic technology, the integration of optoelectronic chips is getting higher and higher, and the waveguide crossing phenomenon is inevitable. The waveguide crossing phenomenon leads to the generation of crossed waveguides. Since the light is totally reflected in the waveguide and suddenly changes to 90° in the crossing area, a large amount of light is excited into high-order modes and leaks into the vertical area, resulting in a large amount of insertion loss and crosstalk. At the same time, before the light enters the crossing area, due to the high refractive index difference, the light is confined in the waveguide; when the light enters the crossing area, the horizontal cladding suddenly disappears, and the light refractive index of the waveguide fails, resulting in diffuse reflection of the light, which further increases the insertion loss and crosstalk.

[0003] In the prior art, there are cross-waveguides based on reverse design or sub-wavelength grating structures. However, such devices often require very high etching processes, have low process tolerances, and have technical problems such as difficulty in mass production or difficulty in controlling production costs. Summary of the invention

[0004] The present invention aims at the technical problems of high process requirements, low fault tolerance and poor platform adaptability of the cross waveguide in the prior art, and provides an optimization method for a multimode cross waveguide, a waveguide, an optical device and a terminal.

[0005] First aspect

[0006] The present invention provides a method for optimizing a multimode cross waveguide, comprising:

[0007] S10, generating a control point set according to the model parameters of the cross waveguide;

[0008] S20, taking the model parameters and the control point set as input, and obtaining a loss value through a loss prediction model;

[0009] S30, optimizing the control point set by a spline curve function, and then taking the optimized control point set as an iteration variable, iteratively executing step S20;

[0010] S40. When the loss value is the smallest, stop the iterative operation and output the control point set corresponding to the smallest loss value.

[0011] Specifically, one of the main technical concepts of the present invention is to present the structural design of the cross waveguide in the form of a control point set, and at the same time, based on the model parameters, reduce the crosstalk of the cross waveguide by optimizing the control point set, so as to achieve the purpose of reducing the difficulty of cross waveguide design and reducing the insertion loss and crosstalk of the cross waveguide, so that the cross waveguide is easy to design and has good anti-crosstalk and anti-insertion loss performance.

[0012] Furthermore, the wear prediction model is a model obtained by training based on a plurality of model samples and a corresponding plurality of point set samples, and a plurality of wear samples corresponding to the model samples and a plurality of point set samples.

[0013] Furthermore, the model parameters include waveguide material, cross-sectional width and transmission wavelength of any input waveguide segment or any output waveguide segment of the cross waveguide;

[0014] The control point set is a point on any spline curve of the central waveguide segment of the cross waveguide, including: a starting point, an ending point, and a characteristic point arranged between the starting point and the ending point.

[0015] Furthermore, the present invention provides a method for optimizing a multi-mode cross waveguide, comprising: the spline curve comprises a B-spline curve, a Bezier curve or a NURBS curve;

[0016] The starting point is the intersection point between adjacent spline curves in the central waveguide segment, the ending point is the intersection point between the spline curve and the input waveguide segment or the output waveguide segment, and the characteristic point is a control point selected on the spline curve.

[0017] Specifically, B-spline curve refers to a special form of representation in numerical analysis, a sub-discipline of mathematics. It is a linear combination of B-spline basis curves; Bezier curve, also known as Bezier curve or Bezier curve, is a mathematical curve used in two-dimensional graphics applications; NURBS curve is a non-uniform rational B-spline curve, which is based on B-spline curve.

[0018] Furthermore, taking the center of the cross waveguide as the coordinate center and the input waveguide segment in any direction as the Y-axis direction, the control point set includes: a starting point (A, W / 2), a first control point (B, C), a second control point (D, E) and an end point (P, Q); W represents the cross-sectional width of the input waveguide segment or the output waveguide segment.

[0019] It can be understood that the starting point and the ending point are restricted control points in the spline curve, and their point coordinates are restricted by the central waveguide segment and the input waveguide segment or the output waveguide segment; while the first control point and the second control point are free control points between the starting point and the ending point, which are used to determine the final contour of the spline curve.

[0020] Furthermore, the function of the spline curve is:

[0021]

[0022] Among them, P(u) represents the function of the B-spline curve, u represents the change in the specified interval, and u∈[u k-1 ,u n+1 ], P i Represents a point on the spline curve, N i , k(u) represents the function of the k-order spline curve, i represents the basis function corresponding to the i-th control point P i , k represents the order of the basis function, which can be any integer between 2 and n+1, and n represents the number of control points minus 1. u i represents the value of the i-th node in the node vector, N i , 0(u) represents the 0th-order basis function.

[0023] Furthermore, the node vector N i , k(u) Is an increasing sequence that defines the parameterization range of the B-spline curve and the supported range of the basis function.

[0024] Second aspect

[0025] The present invention provides a multimode cross waveguide, which is obtained by the optimization method of a multimode cross waveguide provided by any embodiment of the first aspect, comprising: a central waveguide segment, at least two groups of optical paths with the central waveguide segment as the intersection center, and any of the optical paths includes an input waveguide segment and an output waveguide segment;

[0026] The central waveguide section includes a plurality of groups of spline waveguides which are radially distributed with the center of the central waveguide section as the distribution circle center, and each of the spline waveguides is respectively connected to the corresponding input waveguide section and the output waveguide section.

[0027] Furthermore, the spline waveguide includes two symmetrically distributed spline curves, and any one of the spline curves is the outer contour of any side of the spline waveguide;

[0028] The spline curve is identified by the set of control points.

[0029] The third aspect

[0030] The present invention provides an optical device based on a multimode cross waveguide, comprising a multimode cross waveguide as provided in any possible embodiment of the second aspect.

[0031] The fourth aspect

[0032] The present invention provides a terminal, used to implement the multi-mode cross-waveguide optimization method provided in any possible embodiment of the first aspect, comprising:

[0033] Generating unit: generating a control point set according to the model parameters of the cross waveguide, and optimizing the control point set;

[0034] Confirmation unit: takes the model parameters and the control point set as input, obtains the loss value through the loss prediction model; when the loss value is the minimum, stops the iterative operation, and outputs the control point set corresponding to the minimum loss value.

[0035] The terminal includes at least one processor, a communication interface and a memory, the communication interface is used to send and / or receive data, the memory is used to store computer programs, and the at least one processor is used to call the computer program stored in at least one memory to implement a method for predicting optical fiber life as provided in any embodiment of the first aspect.

[0036] It should be noted that the processor included in the terminal described in the fifth aspect above may be a processor specifically used to execute these methods (for convenience of distinction, referred to as a dedicated processor), or a processor that executes these methods by calling a computer program, such as a general-purpose processor. Optionally, at least one processor may include both a dedicated processor and a general-purpose processor.

[0037] Optionally, the computer program may be stored in a memory. Exemplarily, the memory may be a non-transitory memory, such as a read-only memory (ROM), which may be integrated with the processor on the same device or may be separately provided on different devices. The embodiment of the present invention does not limit the type of memory and the configuration of the memory and the processor.

[0038] In summary, the present invention provides a multimode cross-waveguide optimization method, waveguide, optical device and terminal, which have at least the following advantages:

[0039] 1. The present invention presents the structural design of the cross waveguide in the form of a control point set. At the same time, based on the model parameters, the crosstalk of the cross waveguide is reduced by optimizing the control point set, so as to achieve the purpose of reducing the difficulty of the cross waveguide design and reducing the insertion loss and crosstalk of the cross waveguide, so that the cross waveguide is easy to design and has good anti-crosstalk and anti-insertion loss performance;

[0040] 2. The cross-waveguide optimization method provided by the present invention has flexible design and reliable selection of control point sets, and can be applied to more complex and higher performance designs;

[0041] 3. The central waveguide section of the cross waveguide provided by the present invention is constructed based on a spline curve. The cross waveguide has a smoother profile, a larger process tolerance, and a lower manufacturing difficulty, and is suitable for low-cost mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention will be further described in detail below in conjunction with the accompanying drawings and preferred embodiments, but those skilled in the art will appreciate that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be used as a limitation on the scope of the present invention. In addition, unless otherwise specified, the drawings are only schematically representing the composition or structure of the described objects and may contain exaggerated displays, and the drawings are not necessarily drawn to scale.

[0043] Figure 1 A schematic flow chart of a method for optimizing a multimode cross waveguide provided by an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of the structure of a multimode cross waveguide provided by an embodiment of the present invention;

[0045] Figure 3 A schematic diagram of the composition of a spline curve of four control points in a dual light path scenario provided by an embodiment of the present invention;

[0046] Figure 4 A schematic diagram of the composition of a spline curve of six control points in a dual light path scenario provided by an embodiment of the present invention;

[0047] Figure 5 An electric field distribution diagram of a multimode cross waveguide provided by an embodiment of the present invention;

[0048] 1. Input waveguide segment; 2. Output waveguide segment; 3. Central waveguide segment; 4. Substrate; 31. Spline curve; 31a. Starting point; 31b. First control point; 31c. Second control point; 31d. Third control point; 31e. Fourth control point, 31n. End point. DETAILED DESCRIPTION

[0049] The following is combined with Figures 1 to 5 , the present invention is described in detail.

[0050] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0051] The main technical concept of the present invention is to optimize the spline curve 31 of the central waveguide section 3 of the cross waveguide, so as to control the insertion loss and crosstalk of the cross waveguide.

[0052] For further information, see Figure 1 Shown is a schematic flow chart of a method for optimizing a multimode cross-waveguide provided in accordance with an embodiment of the present invention.

[0053] Example 1

[0054] The present invention first generates a control point set according to the model parameters of the cross waveguide through step S10; then, through step S20, the model parameters and the control point set are used as input, and the loss value is obtained through the loss prediction model; then, in step S30, the control point set is optimized through the function of the spline curve 31, and the optimized control point set is used as an iterative variable to iteratively execute step S20; finally, through step S40, when the loss value is the minimum, the iterative operation is stopped, and the control point set corresponding to the minimum loss value is output.

[0055] Furthermore, the judgment of the minimum loss value includes: presetting a loss judgment value, and when the loss value during the iteration process is less than the loss judgment value, determining that the current loss value is the minimum.

[0056] Optionally, a loss iteration value is preset, and when the difference between the loss values ​​in adjacent iteration sequences is less than the loss iteration value, the smallest loss value is determined as the smallest. The loss iteration value is 0.0001 dB-0.01 dB.

[0057] Optionally, the number of iterations is preset, and after the number of iterations is executed, the minimum loss value among them is the minimum loss value.

[0058] Therefore, the present invention can obtain the optimal control point set in the cross waveguide through the above steps, so as to obtain the cross waveguide with the minimum insertion loss and crosstalk, so as to design the optimal cross waveguide structure for the cross waveguides with different model parameters. It is worth explaining that the control point set is the points on the spline curve 31 on the central waveguide segment 3, and the spline curve 31 is the outer contour curve on any side of any spline waveguide of the central waveguide segment 3.

[0059] Example 2

[0060] The loss prediction model provided in Example 1 is a model obtained by training based on multiple model samples and corresponding multiple point set samples, and multiple model samples and multiple loss samples corresponding to the point set samples. It is worth noting that the model samples correspond to model parameters, the point set samples correspond to the control point set, and the loss samples correspond to the loss values.

[0061] Optionally, the loss prediction model is updated through training of model samples, point set samples and loss samples.

[0062] Optionally, the loss prediction model is updated through training of optimized model parameters, control point sets, and loss values.

[0063] For further information, see Figure 2 Shown is a schematic structural diagram of a multi-mode cross waveguide provided by an embodiment of the present invention.

[0064] Example 3

[0065] Based on Embodiment 1 and Embodiment 2, the present invention provides a multimode cross waveguide, the multimode cross waveguide comprising: a central waveguide segment 3 at the intersection center, at least two groups of optical paths with the central waveguide segment 3 as the intersection center, any of the optical paths comprising an input waveguide segment 1 and an output waveguide segment 2; the central waveguide segment 3 comprises a plurality of groups of spline waveguides radially distributed with the center of the central waveguide segment 3 as the distribution circle center, each of the spline waveguides is respectively connected to the corresponding input waveguide segment 1 or the output waveguide segment 2. The input waveguide segment 1, the output waveguide segment 2 and the central waveguide segment 3 are all arranged on a substrate 4. It is worth explaining that the input waveguide segment 1, the output waveguide segment 2 and the central waveguide segment 3 are in the same horizontal space.

[0066] Furthermore, the outer contour of any side of any spline waveguide is the spline curve 31 , and the control point set is the points on the spline curve 31 .

[0067] Optionally, the input waveguide segment 1 on any optical path, the spline waveguide connected to one side of the input waveguide segment 1, the spline waveguide on the other side, and the output waveguide segment 2 connected to the spline waveguide on the other side are located on the same center line, thereby forming a straight optical path.

[0068] For further information, see Figure 3 FIG. 3 is a schematic diagram showing the composition of a spline curve 31 of four control points in a dual light path scenario provided by an embodiment of the present invention.

[0069] Example 4

[0070] The spline curve 31 provided by the present invention is confirmed by 4 points, namely, the starting point 31a, the ending point 31n, the first control point 31b adjacent to the starting point 31a, and the second control point 31c adjacent to the ending point 31n. With the intersection center of the central waveguide segment 3 as the coordinate origin and any light path direction as the Y axis, the control points of the spline curve 31 close to the Y axis coordinate in the first quadrant are concentrated at four points, namely, the starting point 31a (A, W / 2), the first control point 31b (B, C), the second control point 31c (D, E), and the ending point 31n (P, Q), where W represents the cross-sectional width of the input waveguide segment 1 or the output waveguide segment 2. The positions of other spline waveguides are determined by the spline curve 31 close to the Y axis.

[0071] Optionally, in a dual optical path application scenario, the dual optical path multimode cross waveguide is a cross waveguide, and the P value of the end point 31n = Q value, that is, the end point 31n can only be adjusted linearly on Z = Y, and the Z-axis coordinate of the starting point 31a is determined based on the width W of the cross section of the input waveguide segment 1 or the output waveguide segment 2, and only the A value is adjustable.

[0072] It is worth explaining that when the starting point 31a (A, W / 2), the first control point 31b (B, C), the second control point 31c (D, E), and the end point 31n (P, Q) of the spline curve 31 close to the Y-axis coordinate in the first quadrant are confirmed, the spline curve 31 on the other side of the corresponding sample waveguide can be obtained through the Y-axis mirror. Other spline waveguides are obtained based on the number of optical paths.

[0073] Furthermore, the starting point 31 a , the ending point 31 n and the characteristic point are all control points of the spline curve 31 , thereby controlling the linear profile of the spline curve 31 .

[0074] It is worth explaining that the transmission direction of the light path is not affected by Figure 3 The influence of the direction formed by the input waveguide section 1 and the output waveguide section 2, Figure 3 The division is only for the convenience of explaining the optical path. In fact, for the application scenario of the intersection of two optical paths, there are four combinations of optical path transmission directions. The appropriate transmission combination is selected according to the actual needs of the on-chip optoelectronic integrated chip; for example: Figure 3 In the example, the light path in the Y-axis direction has the left side as the input waveguide segment 1 and the right side as the output waveguide segment 2. In fact, the left side of the Y-axis can also be used as the output waveguide segment 2, and the right side as the input waveguide segment 1. The same is true for the light path in the Z-axis direction.

[0075] Optionally, the multimode cross waveguide provided by the present invention can be applied to application scenarios where waveguides of more than two groups of optical paths cross, such as the intersection of three optical paths and the intersection of four optical paths. Figure 3The angle between any adjacent spline waveguides of the provided dual-light path multimode cross waveguide is 90°. After the spline waveguide with the Y axis as the symmetry center is confirmed, the other waveguides are obtained by radial mirroring with the spline waveguide with the Y axis as the symmetry center as the reference. Similarly, when it is necessary to prepare a multimode cross waveguide for three light paths, the angle between any adjacent spline waveguides is 60°; the angle between the multimode cross waveguide for four light paths is 45°...

[0076] For further information, see Figure 4 FIG. 3 is a schematic diagram showing the composition of a spline curve 31 with six control points in a dual light path scenario provided by an embodiment of the present invention.

[0077] Example 5

[0078] Figure 4 A structural schematic diagram of a 6-point controlled spline curve 31 is provided, including a starting point 31a (A, W / 2), a first control point 31b (B, C), a second control point 31c (D, E), a third control point 31d (F, G), a fourth control point 31e (H, I) and an end point 31n (P, Q), so as to be suitable for the structural design of a more complex multi-mode cross waveguide.

[0079] It can be understood that the starting point 31a (A, W / 2) and the end point 31n (P, Q) in the spline curve 31 are permanent points, and the control point is obtained based on the function of the spline curve 31. Therefore, the control point set provided by the present invention can be {starting point 31a, first control point 31b, end point 31n}, {starting point 31a, first control point 31b, second control point 31c, end point 31n}, {starting point 31a, first control point 31b, second control point 31c, third control point 31d, end point 31n}, ..., so as to be applicable to the design of multi-mode cross waveguides in complex scenarios. Among them, the starting point 31a and the end point 31n are permanent points.

[0080] It is worth explaining that the function of spline curve 31 P i It refers to the control point, for example: P in Example 4 0 The starting point is 31a, P 1 is the first control point 31b, P 2 is the second control point 31c, P 4 is the end point 31n, and n in the function of the spline curve is 3; in Example 5, P 0 The starting point is 31a, P 1 is the first control point 31b, P 2 is the second control point 31c, P 3 is the third control point 31d, P 4 is the fourth control point 31e, P5 The end point is 31n, and n in the function of the spline curve is 5; and so on, in other control point set combinations, each control point corresponds to P i , n=i in the function of the spline curve.

[0081] For further information, see Figure 5 Shown is an electric field distribution diagram of a multi-mode cross waveguide provided by an embodiment of the present invention.

[0082] Specifically, the present invention provides an electric field distribution diagram of a multimode cross waveguide based on a dual optical path, see Figure 5 (a), 5(b) and 5(c). Among them, Figure 5 (a) is TE 0 Mode field distribution under mode, Figure 5 (b)TE 1 Mode field distribution under mode, Figure 5 (c)TE 2 Mode field distribution under mode. The light of the multimode cross waveguide obtained by the optimization method of the multimode cross waveguide provided by the present invention is basically confined to the corresponding light path, and the light is basically not scattered into the vertical waveguide, with extremely small insertion loss and crosstalk.

[0083] Further, please refer to Table 1 which is a comparison table of insertion losses in the Y and Z transmission directions of the multimode cross waveguide provided by the present invention and the existing cross waveguide.

[0084] Table 1 Comparison of insertion losses of the multimode cross waveguide provided by the present invention and the existing cross waveguide in the Y and Z transmission directions

[0085]

[0086] In TE 0 TE 1 TE 2 In the three modes, the insertion loss of the multi-mode cross-waveguide provided by the present invention is reduced to varying degrees. The higher the order of the mode, the more obvious the effect of the present invention on improving the loss.

[0087] The present invention is described in detail above. The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the present invention and its core ideas. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for optimizing a multimode cross waveguide, characterized in that: include: S10, generating a control point set according to the model parameters of the cross waveguide; S20, taking the model parameters and the control point set as input, and obtaining a loss value through a loss prediction model; S30, optimizing the control point set by a spline curve function, and then taking the optimized control point set as an iteration variable, iteratively executing step S20; S40. When the loss value is the smallest, stop the iterative operation and output the control point set corresponding to the smallest loss value.

2. A method for optimizing a multimode cross waveguide as claimed in claim 1, characterized in that: The wear prediction model is a model obtained by training based on a plurality of model samples and a corresponding plurality of point set samples, and a plurality of wear samples corresponding to the model samples and the plurality of point set samples.

3. A method for optimizing a multimode cross waveguide as claimed in claim 1 or 2, characterized in that: The model parameters include waveguide material, cross-sectional width and transmission wavelength of any input waveguide segment or any output waveguide segment of the cross waveguide; The control point set is a point on any spline curve of the central waveguide segment of the cross waveguide, including: a starting point, an ending point, and a characteristic point arranged between the starting point and the ending point.

4. A method for optimizing a multimode cross waveguide as claimed in claim 3, characterized in that: include: The spline curve includes a B-spline curve, a Bezier curve or a NURBS curve; The starting point is the intersection of the spline curve and the input waveguide segment or the output waveguide segment, the ending point is the intersection between adjacent spline curves in the central waveguide segment, and the characteristic point is a control point selected on the spline curve.

5. A method for optimizing a multimode cross waveguide as claimed in claim 4, characterized in that: Taking the center of the cross waveguide as the coordinate center and the input waveguide segment in any direction as the Y-axis direction, the control point set includes: a starting point (A, W / 2), a first control point (B, C), a second control point (D, E), and an end point (P, Q); W represents the cross-sectional width of the input waveguide segment or the output waveguide segment.

6. The method for optimizing a multimode cross waveguide according to claim 1, characterized in that: The function of the spline curve is: Among them, P(u) represents the function of the B-spline curve, u represents the change in the specified interval, and u∈[u k-1 ,u n+1 ], P i Represents a point on the spline curve, N i , k(u) represents the function of the k-order spline curve, i represents the basis function corresponding to the i-th control point P i , k represents the order of the basis function, which can be any integer between 2 and n+1, and n represents the number of control points minus 1. u i represents the value of the i-th node in the node vector, N i , 0(u) represents the 0th-order basis function.

7. A multimode cross waveguide, obtained by the optimization method of a multimode cross waveguide according to any one of claims 1 to 6, characterized in that: include: A central waveguide section, and at least two groups of optical paths with the central waveguide section as the intersection center, wherein any of the optical paths includes an input waveguide section and an output waveguide section; The central waveguide section includes a plurality of groups of spline waveguides which are radially distributed with the center of the central waveguide section as the distribution circle center, and each of the spline waveguides is respectively connected to the corresponding input waveguide section and the output waveguide section.

8. A multimode cross waveguide as claimed in claim 7, characterized in that: The spline waveguide comprises two symmetrically distributed spline curves, and any one of the spline curves is the outer contour of any side of the spline waveguide; The spline curve is identified by the set of control points.

9. An optical device based on multimode cross-waveguide, characterized in that: Comprising a multimode cross-waveguide as claimed in claim 7 or 8.

10. A terminal, used to implement the multi-mode cross-waveguide optimization method according to any one of claims 1 to 6, characterized in that: include: Generating unit: generating a control point set according to the model parameters of the cross waveguide, and optimizing the control point set; Confirmation unit: taking the model parameters and the control point set as input, and obtaining the loss value through the loss prediction model; When the loss value is the smallest, the iterative operation is stopped and the control point set corresponding to the smallest loss value is output.

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