偏振模色散对飞秒孤子脉冲传输的影响

The Influence of Polarization Mode Dispersion to Femtosecond Optical Soliton

以Maxwell电磁场理论为基础,在综合考虑了高阶色散、高阶非线性、自相位调制、交叉相位调制、自变陡、脉冲内喇曼散射以及偏振模色散(PMD)等因素的基础上,推导了飞秒孤子脉冲在双折射光纤中传输的耦合非线性薛定谔方程(NLSE)。利用分步傅立叶方法对该方程进行了数值计算,通过对该系统的仿真,研究分析了PMD对飞秒孤子传输的影响。结果发现当PMD参量Dp≤0．1 ps／km1／2时,输出脉冲宽度和峰值功率相对于初始脉冲几乎不变,随着Dp值的增大,脉宽增加,峰值功率降低。当Dp≥1．0 ps／km1／2时,脉冲显著展宽,孤子的两偏振分量发生严重走离。

Based on the Maxwell electromagnetic theory, nonlinear Schroedinger equation（NLSE）, which described the propagation of femtosecoad soliton pulses in fiber-optic, was induced in the presence of high-step dispersion, high-step nonlinearity, self-phase modulation, cross-phase modulation, self-steep, Roman scatter in pulse and polarization mode dispersion （PMD）. With split-step Fourier transform method, some useful results about the PMD influence on femtosecond solitons have been obtained. The results indicate that while the PMD is small like the Dp ≤0.1 ps/km^1/2, the transmission system can hardly be affected by PMD. But, along with the increase of Dp, performances of femtosecond soliton system degrades quickly. If Dp ≥ 1.0 ps/km^1/2, pulses are distinctly broadened and the two polarization parts are seriously departed.