面向中短距应用的差分自相干光纤传输系统  

Differential Self-Coherent Optical Fiber Transmission Systems for Short and Medium Reach Applications

作　　者：蔡轶 姜晨旭 王霄洲 王甫涵 田中星 孙林 王晓玲[1] 刘宁 沈纲祥[1] 周俊 郝祥勇 庞胜清 Cai Yi;Jiang Chenxu;Wang Xiaozhou;Wang Fuhan;Tian Zhongxing;Sun Lin;WangXiaoling;Liu Ning;Shen Gangxiang;Zhou Jun;Hao Xiangyong;Pang Shengqing(School of Electronic and Information Engineering,Soochow University,Suzhou 215006,Jiangsu,China;Hengxin Semitech Co.,Ltd.,Suzhou 215200,Jiangsu,China;Hengtong Group Co.,Ltd.,Suzhou 215200,Jiangsu,China)

机构地区：[1]苏州大学电子信息学院,江苏苏州215006 [2]科大亨芯半导体技术有限公司,江苏苏州215200 [3]亨通集团有限公司,江苏苏州215200

出　　处：《光学学报》2023年第15期107-117,共11页Acta Optica Sinica

基　　金：国家重点研发计划(2022YFB2903000);国家自然科学基金(62275185,62250710164)。

摘　　要：基于4电平脉冲幅度调制(PAM4)的强度调制直接检测(IMDD)是目前中短距应用的主要解决方案之一。然而,基于高阶脉冲调制的IMDD方案检测灵敏度明显下降。另一方面,拥有更高灵敏度的标准相干检测技术又面临成本和复杂度方面的挑战。因此,自零差相干检测(SHCD)和差分检测等自相干检测方案,因其优于PAM4的性能和低于标准相干检测的硬件成本而在新一代中短距应用中具备优势。本文综述和比较自零差相干以及差分自相干检测(DSCD)系统各自的特征、优点和挑战。文中进一步针对光功率受限和光信噪比受限的不同传输场景,分析比较基于SHCD-正交相移键控(QPSK)和DSCD-差分正交相移键控(DQPSK)方案的系统性能,展示了DSCD-DQPSK系统相较其他方案在硬件成本和系统性能方面的综合优势。Significance As cloud computing,the Internet of Things,and 5G technologies rapidly develop,global network traffic has experienced exponential growth.This surge in traffic,both within and between data centers,has fostered an everincreasing demand for high-speed and high-performance optical fiber transmission systems for short-and medium-reach distances.Currently,the intensity-modulation and direct-detection(IMDD)system employing four-level pulse amplitude modulation(PAM4)is the primary solution for cost-sensitive short-and medium-reach transmission scenarios.The IMDD system features a simple structure,low power consumption,and low cost.However,it utilizes only the amplitude dimension of the optical carrier to transmit information,leaving other optical domain dimensions untapped.Additionally,the IMDD system's limited receiver sensitivity poses a challenge when higher-order modulation formats are tried to improve spectral efficiency.Coherent detection systems with higher receiver sensitivity are characterized by utilizing the polarization,phase,and amplitude of optical carriers to transmit information,which leads to higher spectral efficiency.However,their practical implementation in short-to medium-reach transmission scenarios brings about challenges including increased system complexity,higher power consumption of digital signal processing(DSP)chips employed in coherent detection systems,and the need for a high-performance narrow linewidth laser as a local oscillator(LO).These factors limit the widespread adoption of coherent detection in such scenarios.To this end,researchers have explored simplified coherent schemes,including self-homodyne coherent detection(SHCD)and differential self-coherent detection(DSCD)schemes for new-generation short-and medium-reach transmission systems.These schemes strike a balance between system performance and complexity,with higher receiver sensitivity than IMDD systems,and less complexity and costs than standard coherent detection.Among these schemes,the SHCD scheme has caught cons

关 键 词：光通信 相干检测 自相干检测 差分调制 数字信号处理 

分 类 号：TN911.1[电子电信—通信与信息系统]