利用考虑拉曼增益效应的非线性薛定谔方程,在忽略光纤损耗的情况下,采用基于MATLAB的分步傅里叶数值算法,得出线性算符和非线性算符具体的表达式,分步作用于光孤子脉冲传输方程,仿真模拟了光孤子在光纤中传输时的演变.与不考虑拉曼增益的光孤子在光纤中传输相对比,探析了拉曼增益对孤子传输特性的影响.拉曼增益会破坏孤子的传输周期,导致孤子在光纤中传输时快速衰减,并且影响程度和输入孤子的脉冲峰值功率大小有关,拉曼增益对基态孤子和高阶孤子的影响也不相同.
Using the nonlinear Schrdinger equation(NLSE)including Raman gain effect but ignoring fiber loss situation,the linear operator and nonlinear operator specific expression are obtained based on MATLAB fractional Fourier numerical algorithm.They are applied to the NLSE including Raman gain,and the evolutions of soliton pulse are simulated in optical fiber through changing parameters.The result shows that soliton propagation stability is destroyed compared with the case considering no Raman gain,leading to the rapid attenuation of optical soliton.The influence degree depends on input soliton pulse peak power.The effects of Raman gain on ground state soliton and high order soliton are not the same.