利用打靶法对单波长双向抽运拉曼光纤放大器的开关增益问题进行了数值仿真研究,结果表明,在小信号的情况下,只要抽运光的总功率不变,信号光的开关增益几乎与正反向抽运光功率的分配比例无关,此结果和小信号情况下的解析解结论一致。当信号光功率增大到对抽运光的消耗不能忽略时,其开关增益随着正向抽运光功率百分比的增大而略有增大。另外,也给出了几种不同输入信号入纤光功率、不同正反向抽运光功率分配情况下的信号光、正反向抽运光和总光功率沿光纤长度的分布。

On-off gain characteristics of bi-directionally pumped Raman fiber amplifier are numerically simulated through shooting method. The results show that the on-off gain is approximatively independent of forward pump power percentage under constant total pump power. The results are coincided with the analytical solution under small signal power. When the signal power increases till the pump power depletion causing by signal can not be ignored, its on-off gain slightly increases with enhancement of forward pump power percentage under constant total pump power. In addition, the distributions of the signal power, forward pump power, backward pump power and total power along fiber under various input signal power and various forward/back pump power are given through diagram.