基于打靶和遗传算法模拟多阶级联拉曼光纤激光器

直接采用打靶算法数值求解表征光纤中受激拉曼散射效应的非线性耦合方程组对多阶段联拉曼光纤激光器的输出特性进行仿真,任意设置的各阶Stokes光功率初始值会导致计算过程不收敛.本文提出首先采用遗传算法对各阶的Stokes光功率初值进行优化筛选,解决了各阶Stokes光功率初值选择的收敛性问题,然后利用四阶龙格-库塔及打靶算法进行数值求解,结果表明该方法非常有效.在此基础上,对六阶掺锗级联拉曼光纤激光器进行了数值模拟,并比较分析了光纤长度、输出耦合器反射率、泵浦功率等因素对六阶级联拉曼光纤激光器输出特性的影响.

Numerical Algorithm for n Cascaded CW Raman Fiber Lasers Based on Shooting Method and Genetic Algorithm

The problem of poor convergence is existed when arbitrary initial values for Stokes-waves power are employed in the process of numerical mode which the output characteristics of multi-order cascaded Raman fiber lasers using shooting method directly to solve the nonlinear coupled equations used to describe stimulated Raman scattering in fibers.A method of adopting genetic algorithm to determine the region of convergence for the initial values at first,and then solve the coupled equations by Runge-Kutta method and shooting method fast and efficiently is proposed.The effects of fiber length,reflectivity of output coupler and pump power on the output characteristics of a 6th-order cascaded Raman fiber laser are studied on the basis of the proposed method.