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 communication systems, bit synchronization is inaccurate due to chromatic dispersion (CD) and acquisition signal clock bias, affecting the performance of the entire digital receiving system. A modified Gardner timing recovery method for coherent optical differential quadrature phase shift keying (DQPSK) signals is proposed. The proposed method takes into account the characteristics of quadrature phase shift keying (QPSK) signals and the dispersive The characteristics of intersymbol interference generated are based on the fusion of signal time and frequency domain information to reduce the interference of chromatic dispersion and noise on clock recovery. The digital communication system of 40Gb / s Polarization Multiplexed Phase Shift Keying (PM-DQPSK) signal transmission coherent detection is verified by experiments. The results show that this method can effectively resist the influence of dispersion and has good jitter performance.