改进的MPPM-QPSK光通信系统两模均衡算法  

Improved Two Modulus Equalization Algorithm for MPPM-QPSK Optical Communication System

作　　者：于梦晗 郭宏翔 刘宇旸[1,2] 李岩 邱吉芳 洪小斌[1,2] 李蔚 左勇[1,2] 伍剑 Yu Menghan;Guo Hongxiang;Liu Yuyang;Li Yan;Qiu Jifang;Hong Xiaobin;Li Wei;Zuo Yong;Wu Jian(School of Electronic Engineering,Beijing University of Posts and Telecommunications,Beijing 100876,China;State Key Laboratory of Information Photonics and Optical Communications,Beijing University of Posts and Telecommunications,Beijing 100876,China)

机构地区：[1]北京邮电大学电子工程学院,北京100876 [2]北京邮电大学信息光子学与光通信国家重点实验室,北京100876

出　　处：《光学学报》2021年第19期89-97,共9页Acta Optica Sinica

基　　金：国家重点研发计划(2019YFB1803601);国家自然科学基金(62021005,61875019);中央高校基本科研业务基金。

摘　　要：多脉冲位置调制联合正交相移键控(MPPM-QPSK)在接收机灵敏度方面具有明显优势,均衡算法可以有效优化数字相干光通信系统中信号带宽受限和码间串扰带来的影响,提高信号的传输质量。针对恒模算法仅能优化MPPM-QPSK中QPSK部分的问题,对两模均衡算法的内圈参考模值进行改进,提出了一种内圈模值不为0的两模均衡算法。将该算法应用到10 Gbit/s单载波高斯成形和Nyquist成形的MPPM-QPSK相干光通信系统中,并对其内圈模值、抽头数和步长等参数进行优化。实验结果表明,相比使用传统两模算法的系统,本系统的接收机灵敏度优化了约0.1 dB。当脉冲数m=2,4,8,16时,相比不加均衡算法的系统,本系统的接收机灵敏度分别优化了0.9 dB,0.6 dB,0.5 dB,0.4 dB。The multi-pulse position modulation combined with quadrature phase shift keying(MPPM-QPSK) has obvious advantages in receiver sensitivity. Equalization algorithms can effectively cope with the influence of limited signal bandwidth and inter-symbol interference in digital coherent optical communication systems and improve the signal transmission quality. To tackle the problem that only the QPSK part of MPPM-QPSK can be optimized by the constant modulus algorithm, this paper improves the inner-ring reference modulus of the two modulus equalization algorithm and proposes a two modulus equalization algorithm with the inner-ring modulus not 0. The algorithm is applied to the MPPM-QPSK coherent optical communication system of 10 Gbit/s single-carrier Gaussian shaping and Nyquist shaping, and some parameters are optimized, such as the inner-ring modulus, the number of taps and the step length. The experimental results show that the receiver sensitivity of the system is optimized by about 0.1 dB compared with that of the system using the traditional two modulus algorithm. When the number of pulses is set at m=2, 4, 8, 16, the receiver sensitivity of this system is improved by 0.9 dB, 0.6 dB, 0.5 dB and 0.4 dB, respectively, in comparison with the system without equalization algorithm.

关 键 词：光通信 相干通信 混合调制格式 均衡算法 接收机灵敏度 

分 类 号：TN914[电子电信—通信与信息系统]