一种降低相干光正交频分复用系统序列相关性的方法  

A method for serial correlation reduction in coherent optical OFDM system

作　　者：张斯尧[1] 闫连山[1] 叶佳[1] 易安林[1] 潘炜[1] 罗斌[1] 

机构地区：[1]西南交通大学信息科学与技术学院,信息光子与通信研究中心,四川成都610031

出　　处：《光电子．激光》2013年第8期1477-1482,共6页Journal of Optoelectronics·Laser

基　　金：国家基础研究"973"计划(2012CB315704);国家自然科学基金(61275068)资助项目

摘　　要：分析了相干光正交频分复用(CO-OFDM)系统中四波混频(FWM,four-wave mixing)效应对系统性能的影响,提出了一种新的降低CO-OFDM系统中各个子载波序列相关性的方法——偏载波填充法(PCF,partial carrier filling)与部分序列传输(PTS,partial sequence of transmission)相结合。理论分析和仿真表明,这种方法能有效降低CO-OFDM系统的序列相关性,从而抑制信道内FWM效应对CO-OFDM系统带来的损伤。研究结果表明,本文提出的方法在传输距离达103 km的情况下,误码率(BER)仍然低于10-3,与PTS方法相比,降低了将近1个数量级。Coherent optical orthogonal frequency division multiplexing （CO-OFDM） has attracted great research interests over the past few years due to the immunity to fiber chromatic dispersion （CD） and polarization mode dispersion （PMD）. However, CO-OFDM system is very sensitive to fiber nonlinear effects,especially to four-wave mixing （FWM） effects. In CO-OFDM system, the inner-band FWM effect is mainly dependent on serial correlation among the OFDM subcarriers. Therefore, inner-band FWM effect can be mitigated by reducing the serial correlation among the OFDM subcarriers. In this pa- per,we have investigated and theoretically analyzed the effects of inner-band FWM in the CO-OFDM system,and then introduced a novel method to reduce the serial correlation of OFDM subcarriers for mitigating the inner-band FWM effects. Our method combines the partial carrier filling （PCF） and par- tial sequence of transmission （PTS） together. Theoretical analysis and simulation results show that this method can effectively reduce the serial correlation of the CO-OFDM subcarriers, and mitigate the inner- band FWM effects in CO-OFDM system. In addition, simulation results also indicate that the bit-error- rate （BER） of the proposed system keeps lower than 10-3 （one order of magnitude lower than PTS） af- ter being transmitted over 1000 km fiber,which demonstrates the effectiveness of the proposed method.

关 键 词：相干光正交频分复用(CD-OFDM) 序列相关性 四波混频(FWM) 偏载波填充法(PCF) 部分序列传输(PTS) 

分 类 号：TN929.11[电子电信—通信与信息系统]