集总式放大波分复用链路中交叉相位调制的边带不稳定性

Cross-phase modulational sideband instability in wavelength-division-multiplexing system with periodic lumped amplifiers

集总式放大链路中,放大器的周期分布,等效于形成一折射率光栅,它为四波混频提供了相位匹配的条件,产生边带不稳定性.本文通过解析和数值模拟的方法,研究了周期集总式放大链路中,交叉相位调制边带不稳定性.解析研究中,根据耦合方程的稳态解,计算了反常色散与正常色散光纤链路中由于扰动而产生的边带不稳定性的增益;数值模拟中,利用分裂步长傅里叶变换法与Monte_Carlo方法,得出了输出光脉冲的频谱,说明输出光脉冲频谱中产生新的边带.两种方法的计算结果表明,在周期集总式放大光通信链路中,存在交叉相位调制边带不稳定性,两种方法得到的结论基本一致.

Periodically spaced amplifiers along a transoceanic fiber links provide the phase-matching condition for four-wave-mixing because of Kerr nonlinearity. Both analytic method and numerical method are used to study the cross-phase modulational sideband instability in fiber links with periodical lump amplifiers. In the analytic method, the gain of sideband instability is obtained. In the numerical method, by use of split-step Fourier transform method, the frequency spectra of output optical pulses are obtained in normal and anomalous fiber links, and there are sidebands in the spectrum configuration. By comparison of the results from two the methods, they are constant with each other.