利用信号光和插入的连续泵浦光之间产生的交叉相位调制(XPM)效应, 提出了一种基于并联的XPM效应来监测光相位调制信号的一阶偏振模色散(PMD)的新技术。泵浦光的光谱会随着信号光中PMD和色散(CD)的变化而发生变化, 所以导致泵浦光的光功率发生变化, 在并联的一个支路中抑制PMD的影响, 利用并联的两路同一波段泵浦光功率的差值来进行监测。仿真结果显示, 新的技术可以实现对40 Gb/s 非归零差分四相移相键控(NRZ-DQPSK)光信号从0~20 ps的监测。在20 ps的监测范围内, 新技术的动态范围大于3 dB, 可以用来进行准确的监测。对信号速率、色散、泵浦光功率和滤波器带宽对新技术的影响做了详细的研究。

A first-order Polarization Mode Dispersion(PMD) monitoring technique for phase-modulated optical signals was proposed utilizing the cross-phase modulation(XPM) effect between the input signal and the inserted continuous-wave probe in parallel connection. Because of accumulation of PMD, the XPM effect in nonlinear fiber leads to variation of pump phase. This can cause spectrum broadening resulting in variation of pump power. The technique can suppress the influence of PMD in one branch of the two signals in parallel connection. Then the difference of the two pump power at the same band was used to monitor PMD. The simulation shows that the technique can monitor PMD of 40-Gb/s non-return-to-zero differential quadrature phase-shift keying (NRZ-DQPSK) from 0-30 ps. The dynamic range over 3 dB can be used in accurate monitoring compared to existing methods. Study of the effect of signal rate, CD, pump power and filter bandwidth on the new technique was conducted in detail.