计算多波长抽运光纤拉曼放大器传输方程的新方法

提出了一种直接用龙格一库塔迭代算法全面求解光纤拉曼放大器传输方程的方法。求解中不作任何假设近似，综合考虑了抽运、信号、噪声在传输过程中的相互作用。该方法推导过程简单，计算速度较快，能达到较高的精度要求，且有助于深入理解光纤拉曼放大器中各种效应在传输过程中的相互影响。采用此方法成功地在100nm带宽上求得信号增益，取得了较好的增益平坦度。同时给出了抽运功率在光纤传输线上的分布，进而给出了各个波长上的噪声系数。该方法非常适合应用于超宽带多波长抽运光纤拉曼放大器的工程设计。

A Novel Method of Calculating Transmission Equations for Multiwavelength-Pumped Fiber Raman Amplifiers

The Runge Kutta interative algorithm is used to solve the standard propagation equations of fiber Raman amplifiers (FRAs). The analysis includes all the interactions of pumps, signals and noise without any approximation. Applications of the numerical analysis to practical FRA based systems show a great reduction in computation time comparing with the direct integration approach based on ordinary coupled differential equations, while reproducing all the essential system performances precisely. In addition to enhanced computational efficiency, the derived equations can also give deeper insights into the detailed dynamics of FRAs. By making use of this method, flattened signal gains of a multiwavelength pumping FRA with a bandwidth of over 100 nm are successfully calculated and pump power distributions along the transmission fiber are given. Futhermore, noise figures of the FRA are also presented. The method is very suitable to the engineering design of ultrabroad band FRAs with multiwavelength pumps.