高阶色散和饱和非线性下的交叉相位调制不稳定性  

Modulation Instability Induced by Cross-Phase Modulation in Case of High-Order Dispersion and Saturable Nonlinearity

作　　者：钟先琼[1] 向安平[1] 

机构地区：[1]成都信息工程学院光电技术系,四川成都610225

出　　处：《中国激光》2009年第2期391-397,共7页Chinese Journal of Lasers

基　　金：四川省教育厅自然科学重点项目(2006A124);四川省科技厅应用基础项目(05JY029-084);成都信息工程学院科技发展基金(KYTZ20060604)资助项目

摘　　要：从光纤中包含饱和非线性和高阶色散的耦合非线性薛定谔方程组出发,采用线性稳定性分析法,研究了高阶色散和饱和非线性对双光束交叉相位调制不稳定性的综合影响。研究表明,当四阶和二阶色散系数同号时,调制不稳定性增益谱可能出现一个新的远离零点的第二谱区,且该谱区由两个始终相连的小谱区组成;第一谱区的谱峰与第二谱区中靠近零点的小谱区的谱峰相当;在其他色散区,增益谱只存在一个谱区。而饱和非线性的存在则使每个谱区的谱宽、峰值增益大小随入纤功率的增大呈现出先增大后减小的特点,即对每个谱区而言,将出现两个不同的输入功率对应同一个不稳定增益峰值和谱宽的情形。The combined effects of high order dispersion and saturable nonlinearity on modulation instability induced by cross phase modulation of two optical waves are investigated based on the coupled nonlinear Schrodinger equations including saturable nonlinearity and high-order dispersion in optical fibers. And the method of linearstability analysis is adopted. The results show that, when the fourth order dispersion has the same sign as that of the second-order one, a new gain spectral regime called the second gain spectrum which is far away from the zero point may appear. It actually consists of two small spectra which are always linked together. The first gain spectrum has nearly the same peak value as that of the small spectrum close to the zero point of the second gain spectrum. In the other dispersion regimes, the gain spectra consist of only one regime. The existence of the saturable nonlinearity will make the spectral width and the peak gain of every spectral regime increase with the input power before decreasing. That is to say, for every spectral regime, this may lead to a unique value of peak gain and spectral width for two different input powers.

关 键 词：非线性光学 交叉相位调制不稳定性 饱和非线性 高阶色散 

分 类 号：O437[机械工程—光学工程]