掺Tm光纤MOPA准相位匹配单程倍频的单频激光器

为获得0.9 μm近红外波段连续波单频激光输出，用50 mm长的PPLN晶体对掺Tm光纤激光MOPA的连续波1 925.08 nm单频激光输出进行单程倍频，通过聚焦参数和准相位匹配温度优化，在43.4 W基频光功率实现了最高9.07 W的962.5 nm二次谐波输出，转换效率达到20.9%。二次谐波为单纵模运转，水平和竖直方向光束质量因子分别为1.36和1.52。实验中研究了聚焦因子和相位匹配温度对倍频转换效率的影响，并讨论了聚焦条件和准相位匹配温度带宽之间的相互关系。实验结果表明:Tm光纤激光准相位匹配单程倍频是获得0.9 μm波段连续波单频激光输出的有效方法。

Single-frequency laser based on single-pass QPM frequency doubling of Tm-doped fiber MOPA

In order to obtain a 0.9 μm near-infrared continuous-wave single-frequency laser output, a 50 mm long PPLN crystal was used to perform single-pass frequency doubling of the continuous-wave 1 925.08 nm single-frequency laser output of the Tm-doped fiber MOPA, and the temperature was matched by focusing parameters and quasi-phase optimized to achieve 96.95 nm second harmonic output up to 9.07 W at a fundamental optical power of 43.4 W, with a conversion efficiency of 20.9%.The second harmonic was in single longitudinal mode with M2 factors of 1.36 and 1.52 on x and y directions, respectively. The influence of focusing parameter and temperature on the conversion efficiency was experimentally investigated. The relationship between the focusing parameter and phase matching temperature acceptance was also discussed. The experimental results show that Tm-doped fiber laser quasi-phase matching one-way frequency doubling is an effective method to obtain 0.9 μm band continuous wave single frequency laser output.