Optimized blind equalization for probabilistically shaped high-order QAM signals  

作　　者：Fengchu Cao Mingyi Gao Pengfei Wang Xiaodi You Gangxiang Shen 曹凤楚;高明义;王鹏飞;由骁迪;沈纲祥(Jiangsu Engineering Research Center of Novel Optical Fiber Technology and Communication Network,Suzhou Key Laboratory of Advanced Optical Communication Network Technology,School of Electronic and Information Engineering,Soochow University,Suzhou 215006,China)

机构地区：[1]Jiangsu Engineering Research Center of Novel Optical Fiber Technology and Communication Network,Suzhou Key Laboratory of Advanced Optical Communication Network Technology,School of Electronic and Information Engineering,Soochow University,Suzhou 215006,China

出　　处：《Chinese Optics Letters》2022年第8期1-5,共5页中国光学快报（英文版）

基　　金：This work was supported in part by the National Key R&D Program of China(No.2020YFB1805805);the National Natural Science Foundation of China(No.62075147).

摘　　要：Probabilistically shaped(PS)high-order quadrature amplitude modulation(QAM)signals are attractive to coherent optical communication due to increased spectral efficiency.However,standard digital signal processing algorithms are not optimal to demodulate PS high-order QAM signals.Therefore,a compromise equalization is indispensable to compensate the residual distortion.Meanwhile,the performance of conventional blind equalization highly depends on the accurate amplitude radius and distribution of the signals.The PS high-order QAM signals make the issue worsen because of indistinct amplitude distributions.In this work,we proposed an optimized blind equalization by utilizing a peak-density K-means clustering algorithm to accurately track the amplitude radius and distribution.We experimentally demonstrated the proposed method in a PS 256-QAM coherent optical transmission system and achieved approximately 1 dB optical signal-to-noise ratio improvement at the bit error rate of 1×10^(−3).

关 键 词：coherent optical communication probabilistic shaping blind equalization 

分 类 号：TN929.1[电子电信—通信与信息系统] TN911.5[电子电信—信息与通信工程]