一种光正交频分复用系统的联合相位均衡方法

正交频分复用（OFDM）技术加相干接收与数字信号处理法(DSP)的组合是超长距离光通信的理想模型。光OFDM系统对相位噪声十分敏感，必须对相位噪声进行补偿。提出一种基于正交小波基变换的光OFDM系统的联合相位均衡方案。该方案将块状导频周期性地插入OFDM信号，在接收端利用导频信息首先消除各个子载波的公共相位误差，然后采用自适应均衡方式消除每个子载波自身相位误差。仿真结果表明，对于二进制正交振幅键控(4QAM)调制信号，在采用常规的G.652光纤、100 Gb/s的相干光OFDM系统中，该联合相位补偿方法可使信号在满足传输系统的误码性能要求下，传输距离达到1000 km。

Joint Phase Equalization in Optical Orthogonal Frequency Division Multiplexing System

The combination of orthogonal frequency division multiplexing (OFDM) technology, coherent receiver and digital singal processing (DSP) is one of the ideal models in long-haul communication. However, optical OFDM receiver is sensitive to phase noise, so it is necessary to compensate phase noise for optical OFDM systems. A joint phase equalization solution to optical OFDM system based on orthogonal wavelet transform is proposed. In this method, block pilots are periodically inserted into the frame of OFDM signals. At receiver, the phase rotations of pilots are extracted to eliminate common phase difference of each subcarrier. Then, an adaptive equalization is applied to eliminate the phase error inside each subcarrier. Simulation results demonstrate that the proposed method is effective for 100 Gb/s optical binary translation quadrature amplitude modulation (4QAM) OFDM system in which data transmitted over 1000 km with G.652 fiber.