相干光差分正交相移键控系统中改进的Gardner定时恢复方法实验研究  

Experimental Research on Timing Recovery of a Differential Quadrature Phase Shift Keying Coherent Optical Transmission System Based on an Improved Gardner Algorithm

作　　者：刘磊[1,2] 肖江南[1,2] 唐进[1,2] 何晶[1,2] 陈林[1,2] 

机构地区：[1]湖南大学信息科学与工程学院,湖南长沙410082 [2]湖南大学微纳光电器件及应用教育部重点实验室,湖南长沙410082

出　　处：《光学学报》2013年第4期15-21,共7页Acta Optica Sinica

基　　金：国家自然科学基金(60977049);国家863计划(2011AA010203);湖南省自然科学基金(12JJ3070)资助课题

摘　　要：相干光通信系统中由于色散(CD)和采集信号时钟偏差导致了位同步的不准确,影响整个数字接收系统性能。提出了一种适用于相干光差分正交相移键控(DQPSK)信号的改进型Gardner定时恢复方法,该方法综合考虑正交相移键控(QPSK)信号自身特点以及由传输系统中色散而产生的码间干扰的特征,融合了信号时域和频域信息,来降低色散和噪声对时钟恢复的干扰。对40Gb/s偏振复用相移键控(PM-DQPSK)信号传输相干检测数字通信系统进行了实验验证,结果表明,该方法能有效抵抗色散影响,具有较好的抖动性能。In coherent optical transmission system, the inaccurate bit synchronization induced by chromatic dispersion （CD） and local oscillation （LO）frequency modulation （FM） noise reduces the performance of the digital receiver system. To tolerate CD and time jitter, a modified Gardner phase detector for coherent optical differential quadrature phase keying （DQPSK） signal is presented. The proposed scheme, utilizing the features of the signal and inter-symbol interference （ISI）, also combining the information both time and frequency domain of the signal, relieves the impairments to the timing recovery caused by CD and noise. A 40 Gb/s polarization division multiplexed DQPSK （PM-DQPSK） signal transmission and coherent detection digital communication system is experimentally demonstrated. The result shows that the scheme is efficient in resisting CD and has a good performance on time jitter.

关 键 词：光通信 相干光通信 定时恢复 数字相干接收 GARDNER 差分正交相移键控 

分 类 号：TN929.11[电子电信—通信与信息系统]