Polarization dependent loss mitigation method and system based on subcarrier polarization state control

Abstract

The application provides a polarization-related loss relieving method and system based on subcarrier polarization state control, comprising the following steps: S1, initializing a binary bit sequence to obtain a subcarrier polarization state parameter; S2, according to the subcarrier polarization state parameter, different polarization states are given to different subcarriers, and the system factor performance index is obtained through channel transmission; S3, the subcarrier polarization state parameter is iteratively optimized through a genetic algorithm, and the polarization-related loss effect is relieved through the optimization result. The application optimizes the subcarrier polarization state parameter based on the Q factor performance index of an optical communication system through a genetic algorithm, so that the polarization-related loss effect of the optical communication system is relieved and the system performance is optimized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of optical communication, and in particular, relates to a polarization-dependent loss mitigation method and system based on subcarrier polarization state control. BACKGROUND

[0002] In optical communication systems, polarization-dependent loss is a polarization effect caused by link devices. It affects the accumulation of amplified spontaneous emission noise on the link, leading to imbalance in the signal-to-noise ratio between the two polarizations of polarization multiplexed signals, thereby significantly reducing the performance of the communication system.

[0003] The digital signal processing technology in existing transmission systems can effectively compensate for linear impairments such as chromatic dispersion and polarization mode dispersion, but it is difficult to fully compensate for polarization-dependent loss. The common approach is to monitor the size of the polarization-dependent loss and perform brute-force compensation based on the polarization-dependent loss matrix at the receiving end. Considering the close relationship between polarization-dependent loss and signal polarization state, the flexibility of digital subcarrier optical communication systems can be used to mitigate the polarization-dependent loss impairment accumulated along the link by optimizing the polarization state of different subcarriers at the transmitting end. The subcarrier is a concept in communication systems, referring to a small section of resources that can be independently modulated in the frequency domain. In communication systems, the carrier is the basic unit of frequency domain resources, while the subcarrier is a smaller unit of frequency domain resources that can be independently modulated and used.

[0004] Patent document CN111999813A discloses a method for optimizing polarization-dependent loss. The patent proposes changing the propagation angle by establishing a coordinate system to reduce the polarization-dependent loss of filter-type passive devices. However, this patent is based on the optimization of polarization-dependent loss at the device level based on physical characteristics, without considering the signal characteristics in system transmission, and does not propose optimization of polarization-dependent loss at the signal level at the transmitting end.

[0005] Patent document CN113541817A discloses a polarization-dependent loss compensation method for constellation probability shaping related optical communication systems. The patent proposes using the characteristics of polarization multiplexed signals to compensate for the polarization-dependent loss of constellation probability shaping signals without polarization demultiplexing. However, this patent still compensates based on the estimated polarization-dependent loss inverse matrix, does not utilize the flexibility of subcarriers in a subcarrier system, and does not propose a transmitting end optimization scheme. SUMMARY

[0006] In view of the defects in the prior art, the purpose of the present application is to provide a polarization-dependent loss mitigation method and system based on subcarrier polarization state control.

[0007] According to the present invention, a method for alleviating polarization-dependent loss based on subcarrier polarization state control is provided, comprising:

[0008] Step S1: Initialize the binary bit sequence to obtain the subcarrier polarization state parameters;

[0009] Step S2: assigning different polarization states to different subcarriers according to the subcarrier polarization state parameters, and transmitting them through the channel to obtain the system's Q factor performance index;

[0010] Step S3: Iteratively optimize the subcarrier polarization state parameters through a genetic algorithm, obtain and use the optimization results to alleviate the polarization-dependent loss effect.

[0011] Preferably, in step S1:

[0012] Step S1.1: Randomly generate a binary bit sequence of length 5n, where n is the number of subcarriers;

[0013] Step S1.2: Decode the binary bit sequence by dividing it into five bits, and map it to the interval [0, 2π] with a minimum interval of π / 16 to obtain subcarrier polarization state parameters;

[0014] The polarization state parameter of the i-th subcarrier is expressed as:

[0015]

[0016] Among them, θ i is the polarization state parameter of the i-th subcarrier; bitstring i is the binary bit sequence of length 5 corresponding to the i-th subcarrier; decimal is the binary-to-decimal conversion function.

[0017] Preferably, in step S2:

[0018] Step S2.1: Control the polarization states of different subcarriers and assign different initial polarization states to different subcarriers;

[0019] Step S2.2: Multiplex the subcarriers obtained in step S2.1, transmit them through the channel, demodulate the received signal, and then calculate and obtain the system's Q factor performance indicator;

[0020] The system refers to an optical communication system;

[0021] The mathematical expression for polarization state control is:

[0022]

[0023] in, for input subcarrier dual polarization signals, for output subcarrier dual polarization signals, and θ is a subcarrier polarization state parameter;

[0024] The Q factor performance index has a mathematical expression as follows:

[0025]

[0026] Q is the Q factor performance index; erfcinv is an inverse complementary error function; and BER is a system bit error rate.

[0027] Preferably, in the step S3:

[0028] Step S3.1: defining a binary sequence corresponding to the subcarrier polarization state parameter as a chromosome, constructing a population with different subcarrier polarization state parameters, and optimizing the population by a genetic algorithm;

[0029] Step S3.2: performing fitness calculation on the population based on the Q factor performance index to obtain individual fitness;

[0030] Step S3.3: mapping each individual to a probability space of [0, 1] according to the individual fitness, and selecting individuals in an interval by repeatedly generating random numbers falling in a certain interval to obtain a new offspring population;

[0031] Step S3.4: performing chromosome crossover operation and mutation operation on the offspring population;

[0032] Step S3.5: re-executing step S2 until a target iteration number is reached, obtaining and optimizing the results to complete the mitigation of the polarization-dependent loss effect.

[0033] Preferably, in the step S3.2:

[0034] The fitness calculation has a mathematical expression as follows:

[0035] fitness = Q - Q min + 0.01

[0036] Q is the Q factor performance index; fitness is the fitness; Q min is a Q factor value of a system Q factor performance index minimum individual in the population;

[0037] In the step S3.4:

[0038] The chromosome crossover operation on the offspring population includes: setting a crossover occurrence probability to 0.7, and for each two individuals in the new offspring population, generating a random number in an interval of [0, 1], and judging whether the random number is less than the crossover occurrence probability.

[0039] If the result is yes, then randomly select an interval of a chromosome to perform a chromosome crossover operation on two individuals;

[0040] If the result is no, then do not perform a chromosome crossover operation;

[0041] perform a chromosome mutation operation on the offspring population, comprising: setting a mutation occurrence probability to 0.1, generating a random number in the interval [0, 1] for each individual in the new offspring population, and determining whether the random number is less than the mutation occurrence probability;

[0042] If the result is yes, then randomly select a chromosome point to perform a chromosome mutation operation;

[0043] If the result is no, then do not perform a chromosome mutation operation.

[0044] According to the polarization-related loss relieving system based on a subcarrier polarization state control provided by the application, comprising:

[0045] Module M1: initialize a binary bit sequence to obtain a subcarrier polarization state parameter;

[0046] Module M2: according to the subcarrier polarization state parameter, give different polarization states to different subcarriers, and transmit through a channel to obtain a q-factor performance index of the system;

[0047] Module M3: through a genetic algorithm, iteratively optimize the subcarrier polarization state parameter, and through the optimization result, complete the relieving of the polarization-related loss effect.

[0048] Preferably, in the module M1:

[0049] Module M1.1: randomly generate a binary bit sequence with a length of 5n, wherein n is the number of subcarriers;

[0050] Module M1.2: decode the binary bit sequence every five bits, and map to the interval [0, 2π] with π / 16 as the minimum interval to obtain the subcarrier polarization state parameter;

[0051] The polarization state parameter of the i-th subcarrier is mathematically expressed as:

[0052]

[0053] Wherein, θ i is the polarization state parameter of the i-th subcarrier; bitstring i is the binary bit sequence with a length of 5 corresponding to the i-th subcarrier; decimal is a binary-decimal conversion function.

[0054] Preferably, in the module M2:

[0055] Module M2.1: polarization state control is performed on different subcarriers, and different initial polarization states are given to different subcarriers;

[0056] Module M2.2: the subcarriers obtained through the module M2.1 are multiplexed, transmitted through a channel, demodulated for a received signal, and then the Q factor performance index of the system is calculated and obtained;

[0057] The system refers to an optical communication system;

[0058] The polarization state control has a mathematical expression as follows:

[0059]

[0060] Among them, is an input subcarrier dual polarization signal, is an output subcarrier dual polarization signal, and θ is a subcarrier polarization state parameter;

[0061] The Q factor performance index has a mathematical expression as follows:

[0062]

[0063] Among them, Q is the Q factor performance index; erfcinv is the inverse complementary error function, and BER is the system bit error rate.

[0064] Preferably, in the module M3:

[0065] Module M3.1: a binary sequence corresponding to a subcarrier polarization state parameter is defined as a chromosome, different subcarrier polarization state parameters form a population, and the population is optimized through a genetic algorithm;

[0066] Module M3.2: the population is calculated for fitness based on the Q factor performance index, and individual fitness is obtained;

[0067] Module M3.3: according to the individual fitness, each individual is mapped to a probability space of [0, 1], and through the way of repeatedly generating random numbers falling in a certain interval, individuals in the interval are selected to obtain a new offspring population;

[0068] Module M3.4: the offspring population is subjected to chromosome crossover operation and mutation operation;

[0069] Module M3.5: the module M2 is re-executed until a target iteration number is reached, and the optimization result is obtained to complete the mitigation of the polarization-dependent loss effect.

[0070] Preferably, in the module M3.2:

[0071] The calculation of the fitness is mathematically expressed as:

[0072] fitness = Q-Q min +0.01

[0073] Wherein, fitness is fitness, Q min is the Q factor value of the lowest individual of the Q factor performance index of the system in the population;

[0074] In the module M3.4:

[0075] The chromosome crossover operation is performed on the offspring population, including: setting the crossover occurrence probability to 0.7, and for each two individuals in the new offspring population, generating a random number in the interval [0,1], and judging whether the random number is less than the crossover occurrence probability;

[0076] If the result is yes, a chromosome interval is randomly selected to perform chromosome crossover operation on the two individuals;

[0077] If the result is no, no chromosome crossover operation is performed;

[0078] The chromosome mutation operation is performed on the offspring population, including: setting the mutation occurrence probability to 0.1, and for each individual in the new offspring population, generating a random number in the interval [0,1], and judging whether the random number is less than the mutation occurrence probability;

[0079] If the result is yes, a chromosome point is randomly selected to perform chromosome mutation operation;

[0080] If the result is no, no chromosome mutation operation is performed.

[0081] Compared with the prior art, the present application has the following beneficial effects:

[0082] 1、The present application optimizes from the perspective of the polarization state of the signal at the transmitting end by controlling the initial polarization state of different subcarriers, thereby realizing optimization for the polarization-dependent loss effect.

[0083] 2、The present application encodes the polarization state parameters of different subcarriers into a binary bit sequence, thereby being able to find the optimal subcarrier polarization state parameters using a parameter search algorithm.

[0084] 3、The present application optimizes the subcarrier polarization state parameters using a genetic algorithm based on the Q factor performance index of the system, thereby realizing mitigation of the polarization-dependent loss effect of the optical communication system and optimization of the system performance. BRIEF DESCRIPTION OF DRAWINGS

[0085] Other features, objects, and advantages of the application will become more apparent from the following detailed description when read in conjunction with the accompanying drawings:

[0086] Figure 1 The overall flowchart provided by the present application;

[0087] Figure 2 The genetic algorithm flowchart provided by the present application. DETAILED DESCRIPTION

[0088] The present application will be described in detail below with specific embodiments. The following examples will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of changes and improvements can be made. These are within the scope of the present application.

[0089] The signal will be affected by polarization-dependent loss effect during transmission in the optical fiber link, resulting in performance degradation. Polarization-dependent loss effect is closely related to the polarization state of the signal. Digital subcarrier optical communication system provides the possibility for polarization-dependent loss optimization at the transmitting end.

[0090] Polarization-dependent loss is a professional term, and its English is Polarization Dependent Loss;

[0091] According to the polarization-dependent loss mitigation method based on subcarrier polarization state control provided by the present application, comprising:

[0092] Step S1: initialize a binary bit sequence to obtain subcarrier polarization state parameters;

[0093] Step S2: according to the subcarrier polarization state parameters, different polarization states are given to different subcarriers, and the system Q factor performance index is obtained through channel transmission;

[0094] Step S3: the subcarrier polarization state parameters are iteratively optimized by genetic algorithm, and the mitigation of polarization-dependent loss effect is completed through the optimization results.

[0095] In the step S1:

[0096] Step S1.1: randomly generate a binary bit sequence with a length of 5n, wherein n is the number of subcarriers;

[0097] Step S1.2: decode the binary bit sequence every five bits, and map it to the [0, 2π] interval with a minimum interval of π / 16 to obtain the subcarrier polarization state parameters.

[0098] In the step S2:

[0099] Step S2.1: Polarization state control is performed on different subcarriers, and different initial polarization states are given to different subcarriers;

[0100] Step S2.2: The subcarriers obtained in step S2.1 are multiplexed, transmitted through a channel, demodulated for a received signal, and then a Q factor performance index of the system is calculated and obtained.

[0101] In other words, the subcarriers after polarization state control are multiplexed, the process of subcarrier multiplexing is implemented, system transmission is performed, demodulation is completed for a received signal, and then a Q factor performance index of the system is calculated and obtained.

[0102] In the step S3:

[0103] Step S3.1: A binary sequence corresponding to a polarization state parameter of a subcarrier is defined as a chromosome, different polarization state parameters of subcarriers form a population, and the population is optimized by a genetic algorithm;

[0104] Step S3.2: Fitness of the population is calculated based on the Q factor performance index, and individual fitness is obtained;

[0105] Step S3.3: According to the individual fitness, each individual is mapped to a probability space of [0, 1], and by repeatedly generating random numbers falling in a certain interval, individuals in the interval are selected, and a new offspring population is obtained;

[0106] Step S3.4: Chromosome crossover operation and mutation operation are performed on the offspring population;

[0107] Step S3.5: Step S2 is re-executed until a target iteration number is reached, and the optimization result is obtained, and the mitigation of polarization-dependent loss effect is completed.

[0108] In the digital subcarrier optical communication system, different initial polarization states are given to different subcarriers at the transmitting end, and a genetic algorithm is used to optimize the initial polarization states, so as to achieve the mitigation of polarization-dependent loss effect and the optimization of system performance.

[0109] Step 1: Randomly generate a binary sequence to initialize parameters, decode the binary sequence, and obtain polarization state parameters of subcarriers;

[0110] Step 2: Different polarization states are given to different subcarriers based on the polarization state parameters of the subcarriers, the system Q factor performance index is obtained through a transmission system; the system is an optical communication system;

[0111] Step 3: based on the system Q factor performance index, using genetic algorithm to optimize the sub-carrier polarization state parameters, return to step 2 for iteration before reaching the maximum iteration number;

[0112] Step 4: obtain the best sub-carrier polarization state parameters as the optimization result, complete the mitigation of polarization-related loss effect.

[0113] Specifically, in the step 1:

[0114] Step 1.1: randomly generate a binary 0-1 bit sequence with a length of 5n, where n is the number of sub-carriers in the digital sub-carrier optical communication system;

[0115] Step 1.2: decode the binary sequence in every five bits, map to the interval [0, 2π] with π / 16 as the minimum interval, and obtain the sub-carrier polarization state parameters, that is, θ = (θ1, …, θ i ,…,θ n ), where:

[0116]

[0117] where θ i is the polarization state parameter of the i-th sub-carrier; bitstring i is the binary bit sequence with a length of 5 corresponding to the i-th sub-carrier; decimal is a binary-decimal conversion function for converting binary bit sequence to decimal value;

[0118] In the step 2:

[0119] Step 2.1: based on the obtained sub-carrier polarization state parameters, perform polarization state control on different sub-carriers at the transmitting end, and give different initial polarization states to different sub-carriers, the polarization state control is mathematically expressed as:

[0120]

[0121] where [v xi ,v yi ] T is the input sub-carrier dual polarization signal, [v xo ,v yo ] T is the output sub-carrier dual polarization signal, and θ is the sub-carrier polarization state parameter;

[0122] In other words, [v xo ,v yo ] T is the transpose of the row vector [v xo ,v yo ], that is, represents the output subcarrier dual-polarization signal;[v xi ,v yi ] T is the transpose of the row vector [v xi ,v yi ], that is, represents the input subcarrier dual-polarization signal.

[0123] Step 2.2: Subcarrier multiplexing is performed based on the polarization state controlled subcarriers, and the received signal is demodulated by using digital signal processing technology, and the Q factor performance index of the system is calculated and obtained;

[0124] The Q factor performance index has a mathematical expression as follows:

[0125]

[0126] wherein erfcinv is the inverse complementary error function, and BER is the system bit error rate.

[0127] In the step 3:

[0128] Step 3.1: The binary sequence corresponding to the subcarrier polarization state parameter is regarded as a chromosome, and different subcarrier polarization state parameters form a population, and the population is optimized by using a genetic algorithm;

[0129] Specifically, the genetic algorithm belongs to one of the heuristic search algorithms, and is the formal algorithm name, and the flowchart thereof is as shown in Figure 2 .

[0130] Genetic algorithm, namely Genetic Algorithm, for short, GA, was first proposed by John Holland of the United States in the 1970s, and the algorithm is designed according to the evolution law of biological bodies in nature. It is a computational model simulating the natural selection and genetic mechanism of the biological evolution process of Darwin's biological evolution theory, and is a method of searching for an optimal solution by simulating the natural evolution process. The algorithm uses computer simulation operation in a mathematical way, and converts the solving process of a problem into processes such as crossing and mutation of chromosome genes in biological evolution.

[0131] Step 3.2: Fitness of the population is calculated based on the obtained Q factor performance index of the system. Specifically, the higher the system Q factor performance index, the higher the fitness of the individual, and vice versa. The fitness calculation has a mathematical expression as follows:

[0132] fitness=Q-Q min +0.01

[0133] wherein fitness is the fitness, Q minThe Q factor value of the individual with the lowest Q factor performance index in the population.

[0134] Step 3.3: Selection of the population based on the roulette method, and the higher the fitness of an individual, the more likely it is to be selected and inherited to the next generation;

[0135] Specifically, each individual is mapped to the probability space of [0, 1] according to the fitness of the individual, and then individual selection is performed by repeatedly generating random numbers falling in a certain interval until a new offspring population is obtained.

[0136] Step 3.4: Chromosome crossover operation on the offspring population.

[0137] Specifically, the crossover occurrence probability is set to 0.7, and for each two individuals in the new offspring population, a random number in the interval [0, 1] is generated, and if the random number is less than the crossover occurrence probability, a chromosome interval is randomly selected to perform chromosome crossover operation on the two individuals; if the random number is greater than or equal to the crossover occurrence probability, no chromosome crossover operation is performed.

[0138] Step 3.5: Chromosome mutation operation on the offspring population.

[0139] Specifically, the mutation occurrence probability is set to 0.1, and for each individual in the new offspring population, a random number in the interval [0, 1] is generated, and if the random number is less than the mutation occurrence probability, a chromosome point is randomly selected to perform chromosome mutation operation; if the random number is greater than or equal to the mutation occurrence probability, no chromosome mutation operation is performed.

[0140] Specifically, steps S3.4 and S3.5 are sequentially performed, and the purpose is to generate a new chromosome.

[0141] Step 3.6: Return to step 2 and repeat the iterative genetic algorithm optimization process until the specified number of iterations is reached.

[0142] The application also provides a polarization-related loss mitigation system based on subcarrier polarization state control, which can be realized by performing the flow steps of the polarization-related loss mitigation method based on subcarrier polarization state control, that is, those skilled in the art can understand the polarization-related loss mitigation method based on subcarrier polarization state control as the preferred embodiment of the polarization-related loss mitigation system based on subcarrier polarization state control.

[0143] The polarization-related loss mitigation system based on subcarrier polarization state control provided by the application comprises:

[0144] Module M1: initialize a binary bit sequence and obtain a subcarrier polarization state parameter;

[0145] Module M2: according to the sub-carrier polarization state parameters, different polarization states are given to different sub-carriers, and the Q factor performance index of the system is obtained through channel transmission;

[0146] Module M3: the sub-carrier polarization state parameters are iteratively optimized by genetic algorithm, and the mitigation of polarization-related loss effect is completed through the optimization results.

[0147] Those skilled in the art know that, in addition to implementing the system provided by the present application and each device, module, unit thereof in a pure computer readable program code manner, the system provided by the present application and each device, module, unit thereof can also be implemented in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers and embedded microcontrollers, etc. to achieve the same function by logically programming the method steps. Therefore, the system provided by the present application and each device, module, unit thereof can be considered as a hardware component, and the devices, modules, units included therein for implementing various functions can also be considered as structures within the hardware component; the devices, modules, units for implementing various functions can also be considered as both software modules implementing methods and structures within hardware components.

[0148] The specific embodiments of the present application are described above. It needs to be understood that the present application is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essential content of the present application. The embodiments of the present application and the features in the embodiments can be arbitrarily combined with each other without conflict.

Claims

1. A method for alleviating polarization loss based on subcarrier polarization state control, characterized in that: include: Step S1: Initialize the binary bit sequence to obtain the subcarrier polarization state parameters; Step S2: According to the subcarrier polarization state parameters, different polarization states are assigned to different subcarriers, and transmitted through the channel to obtain the system's Factor performance indicators; Step S3: Iteratively optimize the subcarrier polarization state parameters using a genetic algorithm to obtain and use the optimization results to mitigate the polarization loss effect; In step S2: Step S2.1: Control the polarization states of different subcarriers and assign different initial polarization states to different subcarriers; Step S2.2: Multiplex the subcarriers obtained in step S2.1, transmit through the channel, demodulate the received signal, and then calculate and obtain the system Factor performance indicators; The system refers to an optical communication system; The mathematical expression for polarization state control is: in, is the input subcarrier dual polarization signal, is the output subcarrier dual polarization signal, is the subcarrier polarization state parameter; described Factor performance index, mathematical expression is: in, for Factor performance indicators; is the inverse cocomplement error function, is the system bit error rate; In step S3: Step S3.1: defining a binary sequence corresponding to a subcarrier polarization state parameter as a chromosome, forming a population of different subcarrier polarization state parameters, and optimizing the population using a genetic algorithm; Step S3.2: Based on the The factor performance index calculates the fitness of the population to obtain the individual fitness; Step S3.3: Map each individual to the probability space of [0,1] based on its fitness, and select individuals within a certain interval by repeatedly generating random numbers to obtain a new offspring population. Step S3.4: performing chromosome crossover and mutation operations on the offspring population; Step S3.5: Re-execute step S2 until the target number of iterations is reached, and the optimization result is obtained and passed to complete the mitigation of the polarization loss effect.

2. The polarization loss mitigation method based on subcarrier polarization state control according to claim 1, characterized in that: In step S1: Step S1.1: Randomly generate a binary bit sequence of length 5n, where n is the number of subcarriers; Step S1.2: Decode the binary bit sequence into five bits each, and The minimum interval is mapped to interval, obtain the subcarrier polarization state parameters; No. The polarization state parameter of a subcarrier is expressed as follows: in, For the Polarization state parameters of subcarriers; For the The binary bit sequence of length 5 corresponding to the subcarriers; is the binary-decimal conversion function.

3. The polarization loss mitigation method based on subcarrier polarization state control according to claim 2, characterized in that: In step S3.2: The calculation of the fitness is expressed as follows: in, For fitness, is the Q factor value of the individual with the lowest system Q factor performance index in the population; In step S3.4: Performing a chromosome crossover operation on the offspring population, including: setting a crossover probability to 0.7, and generating a random number in the interval [0, 1] for every two individuals in the new offspring population, and determining whether the random number is less than the crossover probability; If the result is yes, a chromosome interval is randomly selected to perform chromosome crossover operation on the two individuals; If the result is no, no chromosome crossover operation is performed; Performing a chromosome mutation operation on the offspring population, including: setting a mutation probability to 0.1, generating a random number in the interval [0, 1] for each individual in the new offspring population, and determining whether the random number is less than the mutation probability; If the result is yes, a chromosome point is randomly selected for chromosome mutation operation; If the result is no, no chromosome mutation operation is performed.

4. A polarization loss mitigation system based on subcarrier polarization state control, characterized in that: include: Module M1: Initializes the binary bit sequence and obtains the subcarrier polarization state parameters; Module M2: According to the subcarrier polarization state parameters, different polarization states are assigned to different subcarriers, and transmitted through the channel to obtain the system's Factor performance indicators; Module M3: Iteratively optimizes the subcarrier polarization state parameters through a genetic algorithm, obtains and uses the optimization results to mitigate the polarization loss effect; In the module M2: Module M2.1: Controls the polarization state of different subcarriers and assigns different initial polarization states to different subcarriers; Module M2.2: Multiplex the subcarriers obtained by module M2.1, transmit them through the channel, demodulate the received signal, and then calculate and obtain the system's Factor performance indicators; The system refers to an optical communication system; The mathematical expression for polarization state control is: in, is the input subcarrier dual polarization signal, is the output subcarrier dual polarization signal, is the subcarrier polarization state parameter; described Factor performance index, mathematical expression is: in, for Factor performance indicators; is the inverse cocomplement error function, is the system bit error rate; In the module M3: Module M3.1: Define the binary sequence corresponding to the subcarrier polarization state parameters as a chromosome, form a population of different subcarrier polarization state parameters, and optimize the population using a genetic algorithm; Module M3.2: Based on the The factor performance index calculates the fitness of the population to obtain the individual fitness; Module M3.3: Map each individual to the probability space of [0,1] based on its fitness, and select individuals within a certain interval by repeatedly generating random numbers to obtain a new offspring population; Module M3.4: performing chromosome crossover and mutation operations on the offspring population; Module M3.5: Re-execute module M2 until the target number of iterations is reached, and the optimization results are obtained and passed to complete the mitigation of the polarization loss effect.

5. The polarization loss mitigation system based on subcarrier polarization state control according to claim 4, characterized in that: In the module M1: Module M1.1: Randomly generate a binary bit sequence of length 5n, where n is the number of subcarriers; Module M1.2: Decode the binary bit sequence into five bits and The minimum interval is mapped to interval, obtain the subcarrier polarization state parameters; No. The polarization state parameter of a subcarrier is expressed as follows: in, For the Polarization state parameters of subcarriers; For the The binary bit sequence of length 5 corresponding to the subcarriers; is the binary-decimal conversion function.

6. The polarization loss mitigation system based on subcarrier polarization state control according to claim 5, characterized in that: In the module M3.2: The calculation of the fitness is expressed as follows: in, For fitness, The Q factor value of the individual with the lowest Q factor performance index of the system in the population; In the module M3.4: Performing a chromosome crossover operation on the offspring population, including: setting a crossover probability to 0.7, and generating a random number in the interval [0, 1] for every two individuals in the new offspring population, and determining whether the random number is less than the crossover probability; If the result is yes, a chromosome interval is randomly selected to perform chromosome crossover operation on the two individuals; If the result is no, no chromosome crossover operation is performed; Performing a chromosome mutation operation on the offspring population, including: setting a mutation probability to 0.1, generating a random number in the interval [0, 1] for each individual in the new offspring population, and determining whether the random number is less than the mutation probability; If the result is yes, a chromosome point is randomly selected for chromosome mutation operation; If the result is no, no chromosome mutation operation is performed.

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