PDM-CO-OFDM系统中基于判决引导与判决反馈的盲相位估计算法

Blind Phase Estimation Algorithms Based on Decision-Directed and Decision-Feedback in PDM-CO-OFDM Systems

对于偏分复用相干光正交频分复用(PDM-CO-OFDM)通信系统,提出了两种盲相位估计算法,一种基于判决引导(DD)的方案,另一种基于判决引导和判决反馈相结合(DD+DF)的方案。随后在112Gb/s的PDM-COOFDM系统中对算法进行了仿真验证,并与传统的导频辅助(PA)算法进行比较,结果表明DD算法在无需导频开销的情况下,可实现良好的相位估计性能,但对激光器线宽的容忍度较差,DD+DF算法对DD算法的相位估计性能及激光器线宽容忍度都有较高的提升,且其相位恢复结果明显优于采用五路导频的PA算法。

For polarization-division-multiplexing coherent optical orthogonal frequency-division-multiplexing （PDM- CO-OFDM） systems, two blind phase estimation algorithms, including the decision-directed （DD） scheme and the DD plus decision-feedback （DF） scheme, are proposed. The proposed algorithms are verified in a 112 Gb/s PDM-CO- OFDM system, and compared with the traditional pilot-aided （PA） algorithm. The simulation results show that the DD algorithm can achieve better performance, but is less tolerant to laser linewidth, the DD＋DF algorithm can greatly improve the performance and the laser-linewidth tolerance of the DD algorithm ,and the phase recovery result is much better than PA algorithm using five pilots.