基于MIMO预均衡的模分复用无源光网络模式间串扰的消除方法  

MIMO Pre⁃Equalization Based Mode Crosstalk Mitigation Method in Mode Division Multiplexing Passive Optical Network

作　　者：欧阳远江 张倩武 黄烨恬 段帅航 袁珂晨 李迎春 宋英雄 汪敏 Ouyang Yuanjiang;Zhang Qianwu;Huang Yetian;Duan Shuaihang;Yuan Kechen;Li Yingchun;Song Yingxiong;Wang Min(Key Laboratory of Specialty Fiber Optics and Optical Access Networks,Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication,School of Communication and Information Engineering,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学通信与信息工程学院特种光纤与光接入网重点实验室,特种光纤与先进通信国际合作联合实验室,上海200444

出　　处：《中国激光》2023年第6期123-132,共10页Chinese Journal of Lasers

基　　金：国家重点研发计划(2021YFB2900800);上海市科委重点项目(20511102400);上海市自然科学基金(20ZR1420900);高等学校学科创新引智计划(D20031)。

摘　　要：为解决模分复用无源光网络(MDM-PON)模式间串扰的问题,本文提出了一种基于多输入多输出(MIMO)预均衡的串扰消除方法。利用帧头插入的时分训练序列,在接收端相干检测后估计信道的冲激响应,并将其用于发送端MIMO均衡器抽头系数的计算。采用线偏振(LP)模式的模分复用(MDM)传输仿真系统对所提方法进行验证,并将所提方法与基于迫零(ZF)预编码的串扰消除方法进行了对比。结果表明:连接5 km少模光纤(FMF)时,与迫零预编码相比,MIMO预均衡使各模式(LP_(01)、LP_(11)、LP_(21)、LP_(31))信号的误码率在满足7%硬判决-前向纠错(HD-FEC)门限时的发送光功率分别降低了3.0 dB、4.1 dB、1.2 dB和9.2 dB。另外,考虑到光纤色度色散的影响,本文进一步提出了带色散预补偿的MIMO预均衡器结构,该结构可以实现对色散的补偿。Objective Passive optical networks(PON)have become one of the main solutions for optical access networks because of their low cost and large bandwidth capacity.With the continuous increase in bandwidth demand,such as high-definition videos and online conferences,in recent years,existing PON technology has faced capacity bottlenecks.Recently,few-mode fiber(FMF)-based mode-division multiplexing(MDM)technology has been proposed,which is expected to further improve the capacity of PON by introducing a new multiplexing dimension to support higher transmission rates and more users.However,for the mode-division multiplexing passive optical network(MDM-PON),which divides users by mode,the mode crosstalk in the FMF causes the user signals to be loaded on different modes to interfere with each other,which affects the transmission performance.To further improve the transmission performance of the MDM-PON,we propose a MIMO pre-equalization based mode crosstalk mitigation method for the MDM-PON and build a simulation system with VPI Transmission Maker for verification.Methods Owing to the point-to-multipoint structure of the MDM-PON downlink,it is impossible to simultaneously receive and eliminate mode crosstalk for all modes at the receiver.Therefore,an MIMO pre-equalization based mode crosstalk mitigation method is proposed in this study.To estimate the downlink channel impulse response,we design a time-division training sequence that is inserted into the frame header.The time-division training sequence consists of the same number of time slots as the modes,and each time slot corresponds to only one mode and contains the corresponding training symbol sequence.The receiver of each mode uses coherent detection and adopts a training sequence-based least mean square(LMS)adaptive algorithm for channel estimation.The channel estimates are fed back to the transmitter for pre-equalization.The transmitter-side MIMO equalizer used in this study has a linear structure and uses the feedback channel impulse response to calculate the tap

关 键 词：光通信 无源光网络 模分复用 多输入多输出 预均衡 模式串扰 

分 类 号：TN915.62[电子电信—通信与信息系统]