Du Heting, Cao Jianqiu, Chen Heng, Huang Zhihe, Chen Jinbao
Appl Opt. 2019 Mar 10;58(8):2010-2020. doi: 10.1364/AO.58.002010.
In this paper, the stimulated Raman scattering (SRS) threshold of the distributed-pumped fiber amplifier consisting of multiple sub-amplifiers is analytically studied based on the rate-equation model. The SRS threshold formula is presented where the predictions agree well with the numerical results. With the help of the formula, the effect of the pumping scheme on the SRS suppression of the distributed-pumped fiber amplifier is systematically investigated. It is found that with a given number of pump injection ports, the SRS suppression can be optimized by making only some of sub-amplifiers counter-pumped with the others bi-directional-pumped. It is also suggested that the first sub-amplifier should be adopted to be counter-pumped for suppressing SRS if only one sub-amplifier can be single-directional-pumped. The variation of SRS threshold with the number of sub-amplifiers is also discussed in detail. We believe that these results can provide significant guidance on understanding and designing distributed-pumped fiber lasers and amplifiers.
本文基于速率方程模型，对由多个子放大器组成的分布式泵浦光纤放大器的受激拉曼散射（SRS）阈值进行了分析研究。给出了SRS阈值公式，其预测结果与数值结果吻合良好。借助该公式，系统地研究了泵浦方案对分布式泵浦光纤放大器SRS抑制的影响。研究发现，在给定泵浦注入端口数量的情况下，仅对部分子放大器采用反向泵浦，其余采用双向泵浦，可优化SRS抑制效果。还提出，如果只有一个子放大器可以单向泵浦，应采用第一个子放大器进行反向泵浦以抑制SRS。此外，还详细讨论了SRS阈值随子放大器数量的变化情况。我们相信这些结果可为理解和设计分布式泵浦光纤激光器及放大器提供重要指导。
