Method of Blind Polarization Demultiplexing in Probabilistic Shaping Constellation Modulation Coherent Optical Communication System

Abstract

The invention discloses a blind polarization demultiplexing method in a probabilistic shaping constellation modulation coherent light communication system, which comprises the following steps of: counting the distribution of s0 components of a transmitting end signal in a Stokes space, and determining two screening intervals; calculating a Stokes vector of the receiving end signal; screening out sample sets G1 and G2 in two screening intervals from the receiving end signal; fitting a plane formed by G1 in the Stokes space, dividing G2 into two clusters of samples in the Stokes space by takingthe plane as an interface, respectively fitting two planes corresponding to the two clusters of samples and corresponding normal vectors, and averaging the two normal vectors to obtain a final normalvector; converting the final normal vector into a polarization rotation inverse matrix, and multiplying the polarization rotation inverse matrix by a receiving end signal to finish polarization demultiplexing. According to the invention, a training sequence does not need to be inserted into a sending end, and high-performance polarization demultiplexing is realized by estimating normal vectors ofa plurality of planes in a Stokes space in the probabilistic shaping constellation modulation coherent optical communication system, so that the communication quality of the coherent optical communication system is improved.

Description

technical field [0001] The invention belongs to the technical field of optical communication, in particular to a method for blind polarization demultiplexing in a probability shaping constellation modulation coherent optical communication system. Background technique [0002] Polarization multiplexing coherent optical communication technology increases the capacity of communication networks by simultaneously transmitting information on two orthogonal polarization states of light. However, when the polarization multiplexed optical signal is transmitted through the optical fiber, its polarization state is randomly rotated due to the influence of polarization mode dispersion. Therefore, the time-varying polarization rotation needs to be estimated and compensated at the receiving end, so as to realize demultiplexing of polarization multiplexed signals. One way of polarization demultiplexing is to use the distribution of data in Stokes space to identify the polarization rotation...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem that the existing blind polarization demultiplexing method based on Stokes space designed for equiprobable distribution constellations is not applicable to probability shaping constellations, the present invention proposes a blind polarization demultiplexing method in a probability shaping constellation modulation coherent optical communication system method, this method not only uses the lowest intensity symbol - the sample point corresponding to the "inner circle QPSK", but also filters out the second lowest intensity symbol by calculating a specific probability density function, so as to realize more accurate estimation of the Polarization Rotation Inverse Matrix

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