对增益调制掺铥光纤激光器展开了系统性探究,基于速率方程与传输方程构建了增益调制掺铥光纤激光振荡器和放大器的数值模型,并通过时域有限差分法进行求解,从理论和实验上探究了不同的泵浦光及激光器结构参数下输出的2 μm激光特性。通过数值仿真和实验优化,获得了高转换效率、窄线宽、单一偏振的2 μm波段纳秒激光输出。种子源振荡器获得了最高功率为796 mW、脉宽为67.9 ns、斜效率为54.4%的脉冲激光;在一级放大器后得到了最高功率为9.13 W、脉宽为50.5 ns的2 μm脉冲激光。数值仿真模型的模拟结果与实验结果较好地吻合,该模型能够为该类型激光器的实验研究和工程设计提供参考。

A systematic research on the gain-switched thulium-doped fiber laser is carried out in this paper. Based on the rate equation and the propagation equation, numerical models of a gain-switched thulium-doped fiber laser oscillator and an amplifier are constructed, and the solution is obtained by the finite difference time domain method. The characteristics of 2 μm laser output under different pump light and laser structure parameters are explored theoretically and experimentally. Through numerical simulation and experimental optimization, the nanosecond laser output at 2 μm band with high conversion efficiency, narrow linewidth, and single polarization is obtained. The seed source oscillator obtains the highest power of 796 mW, pulse width of 67.9 ns, and slope efficiency of 54.4%. A 2 μm pulsed laser with the highest power of 9.13 W and pulse width of 50.5 ns has been obtained after the first-stage amplifier. Simulation results of the numerical simulation model agree well with the experimental results. The model can provide a reference for the experimental research and engineering design of this type of laser.