A polarization control method and device without reset for realizing output of any polarization state

Abstract

The present invention discloses a non-reset polarization control method and device for realizing output of any polarization state. The method includes: obtaining a set of control parameters; randomly disturbing a single-polarization optical signal through a polarization scrambler, inputting it into a polarization controller for polarization control to obtain an output polarization state; calculating a polarization state error according to the output polarization state and a target polarization state; obtaining an input polarization state, performing a micro partial differential calculation according to the input polarization state and a polarization control signal to obtain a Jacobian matrix; performing a singular value decomposition process on the Jacobian matrix to obtain a pseudo-inverse matrix; performing a null space operation constraint process according to the pseudo-inverse matrix and the polarization state error to obtain a control signal variation; updating the polarization control signal according to the control signal variation, and performing polarization control on the polarization controller according to the updated polarization control signal to output the target polarization state. Embodiments of the present invention can realize non-reset polarization control for output of any polarization state, and can be widely applied to the field of optical communication technologies.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technologies, and in particular, to a non-reset polarization control method and device for realizing an output of an arbitrary polarization state. Background Art

[0002] In recent years, the bandwidth of optical fiber communication systems has gradually become difficult to meet the demand for the steep increase in data traffic, and it has become urgent to improve the transmission capacity and efficiency of the systems. With the increase in the optical signal transmission rate, signal impairments caused by the drift of the optical polarization state have become increasingly significant, especially polarization mode dispersion and polarization-dependent loss, etc., which limit the capacity and transmission distance of high-speed optical fiber communication systems. Therefore, it is necessary to perform real-time control on the randomly varying polarization state.

[0003] In the related art, polarization control is mainly achieved through polarization tracking direct detection. The most widely used is the gradient descent algorithm based on dithering. Although the control logic is simple, under limited hardware conditions, complex reset operations are usually required to ensure that the control signal is limited within a certain range, which inevitably leads to an instantaneous drift of the polarization state. In addition, the dithering operation also limits the speed of polarization control and cannot meet the requirement of realizing the stable output of an arbitrary polarization state. In summary, the technical problems existing in the related art need to be solved urgently. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a non-reset polarization control method and device for realizing an output of an arbitrary polarization state to achieve the stable output of an arbitrary polarization state.

[0005] On the one hand, the present invention provides a non-reset polarization control method for realizing an output of an arbitrary polarization state, including:

[0006] Obtaining a set of control parameters, where the set of control parameters includes a target polarization state and a polarization control signal;

[0007] Randomly perturbing a single-polarization optical signal through a polarization scrambler, inputting it into a polarization controller for polarization control, and obtaining an output polarization state;

[0008] Calculating a polarization state error according to the output polarization state and the target polarization state;

[0009] Obtaining an input polarization state, and performing a micro partial derivative calculation according to the input polarization state and the polarization control signal to obtain a Jacobian matrix;

[0010] Performing a singular value decomposition process on the Jacobian matrix to obtain a pseudo-inverse matrix;

[0011] Performing a null space operation constraint process according to the pseudo-inverse matrix and the polarization state error to obtain a control signal variation;

[0012] Update the polarization control signal according to the change amount of the control signal, and perform polarization control on the polarization controller according to the updated polarization control signal to output the target polarization state.

[0013] Optionally, the obtaining the input polarization state includes:

[0014] Perform an inverse calculation on the output polarization state according to the conversion formula to obtain the input polarization state.

[0015] Optionally, the obtaining the input polarization state includes:

[0016] Before the input polarization controller performs polarization control, measure the input polarization state through a polarization meter.

[0017] Optionally, the performing singular value decomposition processing on the Jacobian matrix to obtain the pseudo-inverse matrix includes:

[0018] Perform singular value calculation processing on the Jacobian matrix to obtain the orthogonal basis of the task space, the orthogonal basis of the control space, and the singular value;

[0019] Calculate the pseudo-inverse matrix according to the orthogonal basis of the task space, the orthogonal basis of the control space, and the singular value.

[0020] Optionally, the performing null space operation constraint processing on the pseudo-inverse matrix and the polarization state error to obtain the change amount of the control signal includes:

[0021] Calculate the initial solution according to the pseudo-inverse matrix and the polarization state error;

[0022] Obtain the null space term of the Jacobian matrix and the first step length coefficient and the second step length coefficient;

[0023] Perform calculations according to the first step length coefficient, the second step length coefficient, the initial solution, and the null space term to obtain the change amount of the control signal.

[0024] Optionally, the input polarization controller performs polarization control, including:

[0025] Map the control space of the polarization controller to the Stokes space.

[0026] On the other hand, an embodiment of the present invention further provides a non-resetting polarization control device for realizing arbitrary polarization state output, and the device includes: an optical transmitter, a polarization scrambler, a polarization meter, a polarization controller, a control circuit, and an optical receiver;

[0027] The optical transmitter is used to generate a single-polarization optical signal;

[0028] The depolarizer is used to randomly perturb the single-polarization optical signal to obtain incident light;

[0029] The polarization measuring instrument is used to obtain the polarization state parameters of the incident light and the polarization state parameters of the output light;

[0030] The polarization controller is used to perform polarization state conversion on the incident light according to the feedback control voltage to obtain output light;

[0031] The control circuit is used to receive the polarization state parameters of the incident light and the polarization state parameters of the output light for processing operations and output the feedback control voltage;

[0032] The optical receiver is used to receive the output light.

[0033] On the other hand, an embodiment of the present invention further provides a system, including:

[0034] A first module, configured to obtain a set of control parameters, where the set of control parameters includes a target polarization state and a polarization control signal;

[0035] A second module, configured to randomly perturb a single-polarization optical signal through a depolarizer and input it to a polarization controller for polarization control to obtain an output polarization state;

[0036] A third module, configured to calculate a polarization state error according to the output polarization state and the target polarization state;

[0037] A fourth module, configured to obtain an input polarization state, and perform a partial differential calculation according to the input polarization state and the polarization control signal to obtain a Jacobian matrix;

[0038] A fifth module, configured to perform singular value decomposition processing on the Jacobian matrix to obtain a pseudo-inverse matrix;

[0039] A sixth module, configured to perform null space operation constraint processing according to the pseudo-inverse matrix and the polarization state error to obtain a control signal variation;

[0040] A seventh module, configured to update the polarization control signal according to the control signal variation, and perform polarization control on the polarization controller according to the updated polarization control signal to output a target polarization state.

[0041] On the other hand, an embodiment of the present invention also discloses an electronic device, including a processor and a memory;

[0042] The memory is used to store a program;

[0043] The processor executes the program to implement the method as described above.

[0044] On the other hand, an embodiment of the present invention also discloses a computer-readable storage medium storing a program, and the program is executed by a processor to implement the method described above.

[0045] On the other hand, an embodiment of the present invention also discloses a computer program product or a computer program. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions to enable the computer device to execute the method described above.

[0046] Compared with the prior art, the present invention adopts the above technical solutions and has the following technical effects: According to the input polarization state and polarization control signal, the embodiment of the present invention performs a micro differential calculation to obtain a Jacobian matrix, conducts a modeling analysis based on the Jacobian matrix theory, and uses the null space operation to constrain the control signal, calculates the change amount of the control signal, controls the polarizer to output a target polarization state, and can realize a non-resetting polarization control for outputting any polarization state. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0048] Figure 1 is a flowchart of a non-resetting polarization control method provided by an embodiment of the present application;

[0049] Figure 2 is a structural diagram of a polarization control device provided by an embodiment of the present application;

[0050] Figure 3 is a schematic Poincaré sphere simulation diagram of a polarization control method at different perturbation speeds provided by an embodiment of the present application;

[0051] Figure 4 is a schematic diagram of a control signal realized by simulation provided by an embodiment of the present application;

[0052] Figure 5 is a schematic Poincaré sphere simulation diagram for realizing the control of multiple target polarization states provided by an embodiment of the present application;

[0053] Figure 6 is a schematic Poincaré sphere simulation diagram under special circumstances provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] To make the objectives, technical solutions and advantages of this application more clear and understandable, the following further elaborates on this application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely used to explain this application and are not intended to limit this application.

[0055] In the related art, for a directly detected polarization control system, not only a high-performance polarization controller is required, but also an efficient polarization control algorithm. The most widely used is the gradient descent algorithm based on dithering. Although the control logic is simple, under limited hardware conditions, complex reset operations are usually required to ensure that the control signal is limited within a certain range, which inevitably leads to instantaneous drift of the polarization state. In addition, the dithering operation also limits the speed of polarization control. Currently, most algorithms are only applicable to achieving polarization matching between the local oscillator light and the signal light in a coherent optical communication system. In order to expand the application scenarios, the polarization control system should be able to stably output any polarization state. In view of this, this application provides a non-reset polarization control method for achieving any polarization state output.

[0056] Referring to Figure 1 , an embodiment of the present invention provides a non-reset polarization control method for achieving any polarization state output, including:

[0057] S101. Obtain a set of control parameters, where the set of control parameters includes a target polarization state and a polarization control signal;

[0058] S102. Randomly perturb a single-polarization optical signal through a polarization scrambler, input it into a polarization controller for polarization control, and obtain an output polarization state;

[0059] S103. Calculate a polarization state error based on the output polarization state and the target polarization state;

[0060] S104. Obtain an input polarization state, perform a partial differential calculation based on the input polarization state and the polarization control signal to obtain a Jacobian matrix;

[0061] S105. Perform a singular value decomposition on the Jacobian matrix to obtain a pseudo-inverse matrix;

[0062] S106. Perform a null space operation constraint process based on the pseudo-inverse matrix and the polarization state error to obtain a control signal variation;

[0063] S107. Update the polarization control signal according to the control signal variation, and perform polarization control on the polarization controller according to the updated polarization control signal to output the target polarization state.

[0064] In an embodiment of the present invention, an efficient polarization control method is proposed. It is modeled and analyzed based on the Jacobian matrix theory, and the control signal is constrained by null space operation. By obtaining the Stokes parameters of the output polarization state as feedback variables to form a closed-loop control system, polarization control without reset for outputting any polarization state can be achieved. Specifically, by obtaining a set of control parameters, the set of control parameters includes the target polarization state and the polarization control signal. The target polarization state is the polarization state that is ultimately desired to be output and can be set by itself; the polarization control signal is used to control the polarization controller. In the embodiment of the present invention, the rotation angle of the polarization controller is used as the polarization control signal. The single-polarization optical signal is randomly perturbed by a polarization scrambler and input to the polarization controller for polarization control to obtain the output polarization state, where the single-polarization optical signal can be generated by a laser or the like. Then, the polarization state error is obtained by subtracting the output polarization state from the target polarization state. The input polarization state is obtained, and the Jacobian matrix is obtained by performing a micro-differential calculation based on the input polarization state and the polarization control signal. The calculated Jacobian matrix is subjected to singular value decomposition to obtain the pseudo-inverse matrix, and the control signal variation is obtained by performing null space operation constraint processing based on the pseudo-inverse matrix and the polarization state error. Finally, the polarization control signal is updated according to the control signal variation, and the polarization controller is controlled for polarization control output to obtain the target polarization state.

[0065] Further as a preferred embodiment, the obtaining of the input polarization state includes:

[0066] Performing an inverse calculation on the output polarization state according to the conversion formula to obtain the input polarization state.

[0067] In the embodiment of the present invention, the purpose of the embodiment is to ensure that a randomly input polarization state can be converted into a specified output polarization state under a control signal within a limited range. Among them, the polarization controller is usually a structure in which multiple-stage polarization elements are cascaded, such as a three-stage or more phase retarder cascaded at 45 degrees, 0 degrees, and 45 degrees, and a three-stage or more rotatable wave plate cascaded such as QWP-HWP-QWP. For ease of analysis, the polarization state is described using a three-dimensional Stokes vector. For a polarization controller with m stages in series, the polarization control process can be regarded as a mapping from an m-dimensional control space to a three-dimensional Stokes space (i.e., the task space), where m is a positive integer greater than or equal to 3, denotes the control signal vector, and the mapping formula is as follows:

[0068]

[0069] In the formula, S out denotes the output polarization state, M i (i = 1,…, m) is the Mueller matrix (rotation matrix) of the i-th stage polarization element, is the scalar control signal of the i-th stage Miller matrix, and the control signal vector is expressed as S in represents the input polarization state, and f() represents the mapping relationship.

[0070] The above mapping relationship f: is generally non-linear and is determined by the input polarization state S in and each stage Miller matrix M i During the optical fiber transmission process, the input polarization state changes randomly and infinitely, but the adjustment range of each stage of the polarization controller is always limited. Therefore, the key to the polarization control problem lies in using the control signal within a limited range to configure all polarization components to achieve the conversion from the random input polarization state S in to the target output polarization state S out . Generally speaking, the control signal is linearly related to the angle θ rotating around the rotation axis of the i-th stage, which is related to the control method of the actual polarization controller. For the convenience of analysis, the rotation angle is directly used as the control signal. Specifically, select the three-phase control cascaded polarization controller model of the Miller matrix sequence , that is, the rotation axes of the three-stage Miller matrix are the S3, S1, and S3 axes of the Poincaré sphere coordinate system respectively. According to the above mapping formula model, the conversion formula is:

[0071]

[0072] In the formula, S out represents the output polarization state, is the scalar control signal of the i-th stage Miller matrix, and S in represents the input polarization state.

[0073] Finally, the input polarization state is obtained by performing an inverse calculation on the output polarization state according to the conversion formula.

[0074] Further as a preferred implementation manner, the obtaining of the input polarization state includes:

[0075] Before the input polarization controller performs polarization control, the input polarization state is measured by a polarization meter.

[0076] In the embodiment of the present invention, before the single-polarization optical signal enters the polarization controller for polarization control, the input polarization state can also be measured by a polarization meter for the single-polarization optical signal.

[0077] Further as a preferred implementation manner, a Jacobian matrix is obtained by performing a micro partial differential calculation according to the input polarization state and the polarization control signal;

[0078] In the embodiments of the present invention, each polarization state (normalized Stokes vector) on the Poincaré sphere has only two degrees of freedom, such as longitude and latitude, or azimuth and ellipticity. The Stokes vector is chosen to represent the polarization state because the Stokes parameters are easy to measure and obtain, and it is the best choice for representing the task space. It is known that a polarization controller is usually a cascade of three or more stages of polarization elements, which also means that it is essentially redundant, and there are countless solutions to achieve a certain target polarization state. The existence of redundancy can be used to solve the problem of avoiding singularities.

[0079] When considering the small variations of the control signals the non-linear mapping f can be linearized, and the mapping formula becomes:

[0080]

[0081] where J is a 3×m Jacobian matrix, and ΔS out are respectively the instantaneous small variations in the control space and the Stokes space. The Jacobian matrix is a matrix formed by arranging the first-order partial derivatives of a function in a certain way, defined as representing the best linear approximation of the function f near the differentiable point and its general form is:

[0082]

[0083] In the formula, s i,out represents the output polarization state of the i-th polarization element, represents the rotation angle (control signal) of the i-th polarization element.

[0084] The influence of the small variation of the control signal in each stage of the polarization element on the output polarization state S out i.e., the differential sensitivity of the output polarization state satisfies the following formula:

[0085]

[0086] where M i (i = 1, …, m) is the Mueller matrix (rotation matrix) of the i-th stage of the polarization element, is the scalar control signal of the i-th stage Mueller matrix, is the dynamic polarization eigenstate (DES) vector.

[0087] When the output polarization state is consistent with the dynamic polarization eigenstate (DES) vector the right side of the sensitivity formula is 0, that is, the output polarization state is insensitive to the parameter Insensitive. The maximum change in the output polarization state occurs when it is perpendicular to the DES vector At this time, the maximum value of the differential sensitivity of the output polarization state is equal to the magnitude of the DES vector. For the three-stage polarization controller model S out = M3M2M1S in With a 3×3 Jacobian matrix, it can be deduced that:

[0088]

[0089] Where Is the DES vector of the Mueller matrix M 1,2,3 , and it is also the eigen-rotation axis of each stage of the polarization controller. S', S", S''' = S out Are the output Stokes parameters after passing through the first stage, the second stage, and the third stage of the polarization controller respectively. It can be seen that all column vectors of J are perpendicular to S out , which means that regardless of the input polarization state or the polarization controller configuration, the rank of J always satisfies rank(J) ≤ 2, that is, the three-stage DPC model has an irreversible Jacobian matrix and there is singularity. Under the same theory, for the Jacobian matrices of multi-stage polarization controllers with m ≥ 3, they are all rank(J) ≤ 2 and non-full rank.

[0090] Assume that the input polarization state S of the polarization controller at the current k moment in,k = [s 1,in , s 2,in , s 3,in T It is known that by performing partial differential calculations on the polarization signals {θ1, θ2, θ3}, a 3×3 Jacobian matrix can be obtained:

[0091]

[0092] Where each matrix element is:

[0093]

[0094] Obviously, the Jacobian matrix J depends on the current input polarization state S in,k And the magnitude of the control signal . Set the polarization control system to closed-loop control. ΔS out,k Is the error between the actual output polarization state S out,k After passing through the polarization controller at the k moment and the set target polarization state :

[0095]

[0096] Therefore, the Jacobian matrix can be obtained by performing partial differential calculations based on the input polarization state and the polarization control signal.

[0097] As a further preferred embodiment, the singular value decomposition of the Jacobian matrix is performed to obtain a pseudo-inverse matrix, including:

[0098] Performing singular value calculation on the Jacobian matrix to obtain an orthogonal basis of the task space, an orthogonal basis of the control space, and singular values;

[0099] Calculating a pseudo-inverse matrix according to the orthogonal basis of the task space, the orthogonal basis of the control space, and the singular values.

[0100] In the embodiments of the present invention, based on the above analysis, it is known that the Jacobian matrix of a three-stage and multi-stage polarization controller is non-invertible and has singularity. Considering using the Moore-Penrose (M-P generalized inverse matrix) pseudo-inverse of the Jacobian matrix can avoid singularities and obtain the minimum norm solution of the polarization control linear model:

[0101]

[0102] where J + = J T (JJ T ) -1 is the Moore-Penrose pseudo-inverse of the Jacobian matrix J. The pseudo-inverse solution has the minimum norm among all least squares solutions and can generate the smallest change in the control signal The pseudo-inverse matrix J provides an approximate solution at the singularity. However, in the actual control process, if no further constraints are imposed, the pseudo-inverse solution will inevitably approach the singularity, which will cause a significant increase in the minimized change in the control signal. The pseudo-inverse needs to be estimated through singular value decomposition (SVD). The SVD of a 3×m (m≥3) Jacobian matrix J is expressed as: + where U is a 3×3 orthogonal matrix, V is an m×m orthogonal matrix, and D is a 3×m diagonal matrix, specifically:

[0103]

[0104] where, σ

[0105]

[0106] where, σ i (i = 1, 2, 3) are uniquely determined positive real numbers, called singular values. The column vectors u i of the orthogonal matrix U form the orthogonal basis of the task space, and the column vectors v i of the orthogonal matrix V form the orthogonal basis of the control space. The rank of the Jacobian matrix is r, and the vectors v r+1 ,..., vm is an orthogonal basis of the null space of the Jacobian matrix J. Therefore, the pseudo-inverse matrix J + is expressed as:

[0107]

[0108] That is, the pseudo-inverse matrix is calculated based on the orthogonal basis of the task space, the orthogonal basis of the control space, and the singular values.

[0109] Further as a preferred embodiment, the null space operation constraint processing is performed according to the pseudo-inverse matrix and the polarization state error to obtain the control signal variation, including:

[0110] Calculating an initial solution according to the pseudo-inverse matrix and the polarization state error;

[0111] Obtaining the null space term of the Jacobian matrix, the first step length coefficient, and the second step length coefficient;

[0112] Calculating according to the first step length coefficient, the second step length coefficient, the initial solution, and the null space term to obtain the control signal variation.

[0113] In the embodiment of the present invention, for a redundant polarization controller, countless solutions for achieving a certain target polarization state can be found. All feasible solutions differ from the null space of the Jacobian matrix J by a vector. That is, the general solution is where is the initial solution, N is the null space basis vector of J, and δ is an arbitrary vector. Therefore, when searching for the optimal solution this degree of freedom can be utilized in the null space to apply a further constraint. Select a specific Nδ as the projection on the null space of J to minimize the norm of. That is:

[0114] where I is the identity matrix, I - J + J is the projection operator of the null space of J, and ΔS out is the error between the actual polarization state and the target polarization state. including the initial solution and the null space term Since the linear model is assumed to be used for the local space and may not contain the actual minimum value The step length can be used to approach the optimum That is:

[0115] where μ1 and μ2 are the initial solution and the null space term The step coefficients, i.e., the first step coefficient and the second step coefficient, satisfy 0 < (μ1, μ2) < 1. After obtaining the control signal variable the control signal for the next moment is updated to drive the polarization controller to achieve the output of the target polarization state.

[0116] Further as a preferred embodiment, the input polarization controller performs polarization control, including:

[0117] Mapping the control space of the polarization controller to the Stokes space.

[0118] Referring to Figure 2 an embodiment of the present invention also provides a non-resetting polarization control device for realizing the output of any polarization state. The device includes: an optical transmitter 1, a polarization scrambler 2, a polarization measuring meter 3, a polarization controller 4, a control circuit 5, and an optical receiver 6;

[0119] The optical transmitter is used to generate a single-polarization optical signal;

[0120] The polarization scrambler is used to randomly perturb the single-polarization optical signal to obtain incident light;

[0121] The polarization measuring meter is used to obtain the incident light polarization state parameters and the output light polarization state parameters;

[0122] The polarization controller is used to perform polarization state conversion of the optical signal on the incident light according to the feedback control voltage to obtain output light;

[0123] The control circuit is used to receive the incident light polarization state parameters and the output light polarization state parameters for processing and calculation, and output the feedback control voltage;

[0124] The optical receiver is used to receive the output light.

[0125] In an embodiment of the present invention, the above non-resetting polarization control method for realizing the output of any polarization state is applied to a non-resetting polarization control device for realizing the output of any polarization state. The content in the above method embodiments is applicable to the device embodiments of the present invention. The functions specifically realized by the device embodiments of the present invention are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those of the above method embodiments.

[0126] On the other hand, an embodiment of the present invention also provides a system, including:

[0127] A first module for obtaining a control parameter set, where the control parameter set includes a target polarization state and a polarization control signal;

[0128] The second module is used to randomly perturb the single-polarization optical signal through a polarization scrambler, input it into a polarization controller for polarization control, and obtain the output polarization state.

[0129] The third module is used to calculate the polarization state error based on the output polarization state and the target polarization state.

[0130] The fourth module is used to obtain the input polarization state, perform a micro partial differential calculation based on the input polarization state and the polarization control signal, and obtain the Jacobian matrix.

[0131] The fifth module is used to perform singular value decomposition processing on the Jacobian matrix to obtain the pseudo-inverse matrix.

[0132] The sixth module is used to perform null space operation constraint processing based on the pseudo-inverse matrix and the polarization state error to obtain the control signal variation.

[0133] The seventh module is used to update the polarization control signal according to the control signal variation, and perform polarization control on the polarization controller according to the updated polarization control signal, and output the target polarization state.

[0134] In the embodiments of the present invention, the content in the above method embodiments is applicable to the device embodiments of the present invention. The functions specifically implemented by the device embodiments of the present invention are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those of the above method embodiments.

[0135] In the simulation, the MATLAB mathematical software is used to build a polarization control system simulation platform as Figure 2 shown. The optical transmitter emits linearly polarized light with Stokes components always being (1, 0, 0). The scrambling speed of the polarization scrambler model can be freely set. Among them, the rotation speed of the polarization state changes with the scrambling speed, and the phase angle changes randomly. The system loop delay is set to 200 ns. Select three phase control type cascaded polarization controller models of the Mueller matrix sequence , that is, the rotation axes of the three-stage Mueller matrix are the S3, S1, and S3 axes of the Poincaré sphere coordinate system respectively. The target polarization state is set to [1, 0, 0] T , and the polarization state control effects before and after passing through the system at different scrambling speeds are as Figure 3 shown. At 100 krad / s, the corresponding three-stage drive control signals (unit: π) of the polarization controller are as Figure 4 shown. The control of other arbitrary target polarization states is as Figure 5 shown.

[0136] There are special cases in practical applications. For example, the desired polarization state target may not be a single point on the Poincaré sphere, but a specific region. For instance, in coherent communication, it is often necessary to achieve the orthogonal polarization matching of the local oscillator light, that is, all points with s1 = 0. In this case, the three-stage polarization controller has a one-dimensional output task space and a 1×3 Jacobian matrix J. At this time, only one Stokes parameter s needs to be obtained 1,out . The polarization control effect when the polarization scrambling speed is 100 krad / s is as Figure 6 shown

[0137] Compared with Figure 1 the method, an embodiment of the present invention further provides an electronic device, including a processor and a memory; the memory is used to store a program; the processor executes the program to implement the method as described above

[0138] Compared with Figure 1 the method, an embodiment of the present invention further provides a computer-readable storage medium. The storage medium stores a program, and the program is executed by a processor to implement the method as described above

[0139] An embodiment of the present invention also discloses a computer program product or a computer program. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the computer device can read the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions to enable the computer device to execute Figure 1 the method shown

[0140] In some alternative embodiments, the functions / operations mentioned in the block diagram may not occur in the order mentioned in the operation diagram. For example, depending on the functions / operations involved, two consecutive blocks shown can actually be executed substantially simultaneously or the blocks can sometimes be executed in the reverse order. In addition, the embodiments presented and described in the flowcharts of the present invention are provided by way of example for the purpose of providing a more comprehensive understanding of the technology. The disclosed method is not limited to the operations and logical flows presented herein. Alternative embodiments are foreseeable, in which the order of various operations is changed and the sub-operations described as part of a larger operation are executed independently

[0141] In addition, although the present invention has been described in the context of functional modules, it should be understood that, unless otherwise stated to the contrary, one or more of the functions and / or features described may be integrated in a single physical device and / or software module, or one or more functions and / or features may be implemented in separate physical devices or software modules. It should also be understood that a detailed discussion of the actual implementation of each module is not necessary for understanding the present invention. Rather, given the attributes, functions, and internal relationships of the various functional modules in the devices disclosed herein, the actual implementation of the modules will be understood within the ordinary skills of an engineer. Thus, those skilled in the art can implement the present invention as set forth in the claims without undue experimentation. It should also be understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present invention, which is determined by the full scope of the appended claims and their equivalents.

[0142] If the described functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0143] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a predefined sequence of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in conjunction with these instruction execution systems, apparatuses, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0144] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection (electronic device) having one or more wirings, a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable media can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, then editing, interpreting, or otherwise processing it as appropriate, and then storing it in a computer memory.

[0145] It should be understood that various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), and the like.

[0146] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0147] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

[0148] The above has specifically described the preferred embodiments of the present invention, but the present invention is not limited to the described embodiments. Those skilled in the art can also make various equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A polarization control method without reset for achieving an output of an arbitrary polarization state, characterized in that, The method includes: Obtaining a set of control parameters, where the set of control parameters includes a target polarization state and a polarization control signal; Randomly perturbing a single-polarization optical signal through a polarization scrambler, inputting it into a polarization controller for polarization control, and obtaining an output polarization state; Calculating a polarization state error based on the output polarization state and the target polarization state; Obtaining an input polarization state, and performing a micro partial differential calculation based on the input polarization state and the polarization control signal to obtain a Jacobian matrix; Performing a singular value decomposition process on the Jacobian matrix to obtain a pseudo-inverse matrix; Performing a null space operation constraint process based on the pseudo-inverse matrix and the polarization state error to obtain a control signal variation; Updating the polarization control signal according to the control signal variation, and performing polarization control on the polarization controller according to the updated polarization control signal to output the target polarization state; The performing a null space operation constraint process based on the pseudo-inverse matrix and the polarization state error to obtain a control signal variation includes: Calculating an initial solution based on the pseudo-inverse matrix and the polarization state error; Obtaining a null space term of the Jacobian matrix, a first step length coefficient, and a second step length coefficient; Calculating based on the first step length coefficient, the second step length coefficient, the initial solution, and the null space term to obtain a control signal variation; Among them, for the redundant polarization controller, there are countless solutions to achieve a certain target polarization state. All feasible solutions differ from the null space of the Jacobian matrix J by a vector, that is, the general solution is where is the initial solution, N is the null space basis vector of J, and δ is an arbitrary vector; therefore, when searching for the optimal solution , further constraints can be imposed on by utilizing the degrees of freedom in the null space; select a specific Nδ as the projection on the null space of J to minimize the norm of; that is: where I is the identity matrix, I - J + J is the projection operator onto the null space of J, ΔS out is the error between the actual polarization state and the target polarization state; includes the initial solution and the null space term J + represents the pseudo-inverse matrix; Since the linear model is assumed to be used in the local space, it may not contain the actual minimum value The step size can be used to approach the optimum That is: where μ1 and μ2 are the initial solutions respectively and the step coefficients of the null space term That is, the first step coefficient and the second step coefficient, satisfying 0 < (μ1, μ2) < 1; after obtaining the control signal variable Update the control signal at the next moment to drive the polarization controller to achieve the output of the target polarization state.

2. The method according to claim 1, characterized in that, The obtaining an input polarization state includes: Performing an inverse calculation on the output polarization state according to a conversion formula to obtain an input polarization state.

3. The method according to claim 1, wherein The obtaining an input polarization state includes: Before the input polarization controller performs polarization control, measuring the input polarization state through a polarization meter.

4. The method according to claim 1, wherein The performing a singular value decomposition process on the Jacobian matrix to obtain a pseudo-inverse matrix includes: Performing a singular value calculation process on the Jacobian matrix to obtain an orthogonal basis of the task space, an orthogonal basis of the control space, and singular values; Calculating a pseudo-inverse matrix based on the orthogonal basis of the task space, the orthogonal basis of the control space, and the singular values.

5. The method according to claim 1, wherein The input polarization controller performing polarization control includes: Mapping the control space of the polarization controller to the Stokes space.

6. A polarization control device without reset for realizing output of any polarization state, the device being applied to the control method according to any one of claims 1-5, characterized in that, The device includes: an optical transmitter, a polarization scrambler, a polarization meter, a polarization controller, a control circuit, and an optical receiver; The optical transmitter is configured to generate a single-polarization optical signal; The polarization scrambler is configured to randomly perturb the single-polarization optical signal to obtain an incident light; The polarization meter is configured to obtain incident light polarization state parameters and output light polarization state parameters; The polarization controller is configured to perform an optical signal polarization state conversion on the incident light according to a feedback control voltage to obtain an output light; The control circuit is configured to receive the incident light polarization state parameters and the output light polarization state parameters for processing operations and output the feedback control voltage; The optical receiver is configured to receive the output light.

7. A polarization control system without reset for realizing the output of any polarization state, characterized in that, The system includes: A first module configured to obtain a set of control parameters, where the set of control parameters includes a target polarization state and a polarization control signal; A second module configured to randomly perturb a single-polarization optical signal through a polarization scrambler, input it into a polarization controller for polarization control, and obtain an output polarization state; A third module, configured to calculate a polarization state error according to the output polarization state and the target polarization state; A fourth module, configured to obtain an input polarization state, perform a micro partial differentiation calculation according to the input polarization state and the polarization control signal, and obtain a Jacobian matrix; A fifth module, configured to perform a singular value decomposition process on the Jacobian matrix to obtain a pseudo-inverse matrix; A sixth module, configured to perform a null space operation constraint process according to the pseudo-inverse matrix and the polarization state error to obtain a control signal variation; A seventh module, configured to update the polarization control signal according to the control signal variation, and perform polarization control on the polarization controller according to the updated polarization control signal to output a target polarization state; The sixth module, configured to perform a null space operation constraint process according to the pseudo-inverse matrix and the polarization state error to obtain a control signal variation, includes: Calculating an initial solution according to the pseudo-inverse matrix and the polarization state error; Obtaining a null space term of the Jacobian matrix, a first step coefficient, and a second step coefficient; Calculating a control signal variation according to the first step coefficient, the second step coefficient, the initial solution, and the null space term; Among them, for the redundant polarization controller, there are countless solutions to achieve a certain target polarization state. All feasible solutions differ from the null space of the Jacobian matrix J by a vector, that is, the general solution is where is the initial solution, N is the null space basis vector of J, and δ is an arbitrary vector; therefore, when searching for the optimal solution it is possible to impose further constraints on by utilizing the degrees of freedom in the null space; select a specific Nδ as the projection on the null space of J to minimize the norm of; that is: where I is the identity matrix, I - J + J is the projection operator onto the null space of J, ΔS out is the error between the actual polarization state and the target polarization state; includes the initial solution and the null space term J + represents the pseudo-inverse matrix; Since the linear model is assumed to be used for local space, it may not contain the actual minimum value The step size can be used to approach the optimum That is: where μ1 and μ2 are the initial solutions respectively and the step coefficients of the null space term i.e., the first step coefficient and the second step coefficient, satisfying 0 < (μ1, μ2) < 1; after obtaining the control signal variable update the control signal at the next moment to drive the polarization controller to achieve the output of the target polarization state.

8. An electronic device, characterized in that, The electronic device includes a memory and a processor; The memory is used for storing a program; The processor executes the program to implement the method according to any one of claims 1 to 5.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, the method according to any one of claims 1 to 5 is implemented.

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