提出一种用于相干光正交频分复用系统的公共相位噪声补偿算法。该算法采用二维投影直方图的公共相位噪声盲估计方法,并充分结合了基于导频的相位噪声估计方法,实现了对公共相位噪声的有效补偿。利用少量的梳状导频对频域符号的公共相位噪声进行初始估计和补偿;再将初始补偿后的频域符号的星座图映射到二维数字图像,利用二维投影直方图进行更精细的公共相位噪声补偿。为了验证算法性能,搭建了基于MATLAB和OptiSystem的20 Gbit/s仿真系统,并在标准单模光纤中传输50 km。结果表明,该算法能有效解决投影直方图盲估计算法以π/2为周期的偏差问题,而且仅需少量的导频就能实现比传统导频辅助算法更高的误码性能。

In this paper, we propose a novel algorithm for compensating the common phase noise in coherent optical orthogonal frequency division multiplexing system. The proposed algorithm adopts the common phase noise blind estimation method which is based on the two-dimensional projection histogram,and a pilot-aided phase noise estimation method is combined, thereby realizing the effect compensation for the common phase noise. First, the common phase noise of frequency domain symbols caused by few comb-type pilots can be estimated initially and compensated. Second, by using the two-dimensional projection histogram, the constellation of received signals can be mapped in two-dimensional digital images, and the fine compensation for the common phase noise can be achieved. To verify the performance of our scheme, we build a 20 Gbit/s simulation system based on the commercial OptiSystem and MATLAB over 50 km standard single mode fiber transmission. The corresponding results show that, the proposed algorithm can solve the problem that the bias with period of π/2 exists in the projection histogram blind estimation algorithm. Compared to the traditional pilot-aided scheme, our scheme uses only fewer numbers of pilots and achieves better bit error ratio performance.