为系统地研究同向抽运光纤拉曼放大器的功率转换效率, 采用求数值解和求近似解析解两种方法得到相关结果, 并对其结果进行了比较。首先, 由耦合微分方程出发, 采用龙格库塔算法对功率转换效率进行数值模拟, 同时采用求近似解析解的方法推导出功率转换效率公式; 然后, 给出两种方法下各个参量影响功率转换效率的定量分析结果; 最后, 对分析功率转换效率的两种方法得到的结果进行了比较。结果表明, 两种方法下, 各参量对功率转换效率影响的总体趋势一致。功率转换效率都随着光纤长度增加而增加, 直到增加至一确定值而保持不变, 随着初始信号光功率、光纤拉曼增益系数数值增加而增加, 随着光纤有效面积、抽运光与信号光的频率比数值增加而减小; 功率转换效率和初始抽运光功率都呈抛物线曲线关系; 不同的是, 求解析解的结果大于求数值解的结果。求数值解的结果精确, 优于求近似解析解的结果。所得结论与文献相比有新的进展, 为光纤拉曼放大器功率转换效率的进一步研究提供了参考。

In order to analyze power conversion efficiency of forward pumped fibre Raman amplifier(FRA), comparison of results which are gived by two analysis method both numeric simulation and analytical method is presented. At first, numeric simulation of the coupling equations of FRA was provided with Runge-Kutta method, and theoretical derivation of power conversion efficiency was gived at the same time. Then, the effect of different parameter on forward pumped FRA’s power conversion efficiency have been detailedly investigated with two analysis method. At last, two analysis method’s results are compared. It is found that: they are similar to each other, power conversion efficiency will increase when the fibre length increases, until it has reached the maximum; power conversion efficiency will increase when initial signal power or Raman gain coefficient is larger, and power conversion efficiency will decrease when fibre efficient area or the pump and signal frequency ratio is larger; the relation between power conversion efficiency and initial pump power is para-curve. But power conversion efficiency by analytical method is bigger than power conversion efficiency by numeric simulation, and numeric simulation is more accurate under certain condition. The results are more all-round than in literature, which is helpful for more study of FRA.