基于无波长偏移光学相位共轭的信号损伤补偿  

Signal Impairments Compensation Based on Wavelength-Shift-FreeOptical Phase Conjugation

作　　者：巩小雪 肖汶玲 张琦涵 张天天 尹星 郭磊[1] Gong Xiaoxue;Xiao Wenling;Zhang Qihan;Zhang Tiantian;Yin Xing;Guo Lei(School of Communication and Information Engineering,Chongqing University of Posts and Telecommunications,Chongqing 400065,China;School of Computer Science and Engineering,Northeastern University,Shenyang 110819,Liaoning,China)

机构地区：[1]重庆邮电大学通信与信息工程学院,重庆400065 [2]东北大学计算机科学与工程学院,辽宁沈阳110819

出　　处：《光学学报》2024年第7期44-50,共7页Acta Optica Sinica

基　　金：国家重点研发计划项目(2023YFB2906200);国家自然科学基金资助项目(62075024,62025105,62071076,62221005);重庆市教委创新研究群体项目(CXQT21019)。

摘　　要：为了解决强度调制-直接检测正交频分复用(IM-DD OFDM)光通信系统中由光纤色散和非线性效应导致的传输性能下降的问题,提出利用正交偏振泵浦非简并四波混频(NFWM)产生的无波长偏移光学相位共轭(OPC)波对系统中的信号损伤进行光域补偿。首先在理论上推导了利用正交偏振泵浦NFWM生成OPC波的原理,基于上述原理,设计了无波长偏移OPC实现方式,在正交偏振态上得到与原信号波长完全一致的OPC波。然后对影响生成OPC波功率的因素进行了具体分析。最后依据优化参数设置,进行仿真验证,结果表明所提系统能够以114.375 Gbit/s的传输速率在长度为240 km的标准单模光纤链路中传输。Objective Maximizing the transmission capacity of individual wavelength channels is necessary to meet the increasing capacity and distance requirements of metro optical networks.Orthogonal frequency division multiplexing(OFDM)technology can tolerate certain chromatic dispersion when signals are loaded onto each subcarrier,thus maximizing the transmission capacity within limited bandwidths during optical fiber transmission.In addition,intensity modulation-direct detection(IM-DD)is currently the most widely used method in metro optical network access layers.However,it is severely affected by fiber chromatic dispersion and cannot meet the needs of long-distance transmission in other layers of metro optical networks.Therefore,the IM-DD OFDM system combining the two technologies has received increasing attention.However,as the capacity and distance requirements of next-generation metro optical networks increase further,the dispersion problem will exceed the tolerable limit of OFDM,and the impact of nonlinear effects will become more obvious,causing a serious decline in system performance.Digital back-propagation(DBP)and optical phase conjugation(OPC)technologies are commonly used to compensate for chromatic dispersion and nonlinear effects simultaneously.However,DBP requires solving the inverse non-linear Schrodinger equation of the fiber channel,which has a high computational cost.When using OPC technology,when two sections of fiber have the same length,the even-order chromatic dispersion and pulse broadening caused by nonlinear effects accumulated in the first section of fiber will be completely recovered in the second section of fiber theoretically.However,traditional OPC schemes based on single-pump degenerate four-wave mixing(DFWM)have signal wavelength shifts at the phase conjugator,which changes the group velocity dispersion parameters in the second section of the fiber link.As a result,the OPC needs to be slightly shift from the midpoint of the fiber link to achieve complete signal impairment compensation.Ther

关 键 词：光通信 强度调制-直接检测 正交频分复用 色散补偿 非线性抑制 光学相位共轭 

分 类 号：TN913.7[电子电信—通信与信息系统]