色散缓变掺铒光纤放大器的调制不稳定性

Modulation instability in dispersion-decreasing erbium-doped fiber amplifier

由于掺铒光纤放大器(EDFA)存在增益,相比于传输光纤它有较小的调制不稳定性阈值,使其很容易受到调制不稳定性的影响.本文用微扰法分析基本的非线性薛定谔方程,研究色散缓变掺铒光纤放大器的调制不稳定性,分析其调制不稳定性积分增益谱与输入信号功率、放大器增益、放大器的长度、光纤纵向色散变化参量的关系.结果显示增大光纤纵向色散变化参量值是减小调制不稳定性对放大器影响的有效途径.通过分析调制不稳定增益产生长度,表明合理的选择放大器的长度可以消除调制不稳定性增益的产生.

The existence of gain in erbium-doped fiber amplifiers （EDFA） lowers the threshold for modu-lation instability considerably compared with the case of undoped fibers ,w hich makes it very vulnerable to the influence of modulation instability .Modulation instability in dispersion -decreasing erbium -doped fiber amplifier is studied through a perturbation analysis of the underlying nonlinear Schrodinger equation .The relations of integral gain spectrum of modulation instability to the input signal power , amplifier gain ,the length of amplifiers ,optical fiber longitudinal dispersion change parameters are ana-lyzed .The results show that increasing fiber longitudinal dispersion change parameter is an effective way to diminish the impact of modulation instability to amplifier ,and modulation instability gain spectrum can be eliminated through making use of amplifier length of reasonable choice by analyzing modulation instability gain’s generation length .