6.7 kW全国产化窄线宽三包层光纤激光器

Home-made 6.7 kW narrow linewidth triple-cladding fiber laser

为了实现高功率光纤激光的窄线宽输出,研究了基于大模场三包层掺镱光纤(LMA-YTF)高功率窄线宽光纤激光的热效应和四波混频(FWM)效应。基于FWM效应模型,仿真分析了大模场三包层光纤(LMA-TCF)放大器光谱展宽的影响因素。建立了LMA-YTF的热分布模型,分析了大模场三包层光纤(LMA-YTF)中第二包层功率占比对光纤温度以及泵浦功率上限的影响,讨论了聚合物涂层导热系数和外部温度对光纤温度的影响,实验对比了不同反向合束器的泵浦功率上限,结果表明第二包层功率占比低的(6+1)×1合束器比(9+1)×1合束器拥有更高的泵浦功率上限。基于全国产化器件搭建了一台三包层光纤激光器,实现了输出功率6.7 kW、3 dB线宽为0.32 nm的激光输出。

In order to achieve high-power output of fiber lasers with narrow linewidth,the thermal effect and the four-wave mixing(FWM)effect of the Yb3+doped large mode area triple-cladding fiber(LMA-YTF)based fiber laser was investigated.Based on the FWM effect model,the influences on the spectral broadening of the large mode area triple-cladding fiber(LMA-TCF)amplifiers were simulated and analyzed.Thermal distribution model of the LMA-YTF was modeled.The effects of the power ratio in the second cladding on the fiber temperature characteristics and the upper limit of the pump power were analyzed.The influence of the thermal conductivity of polymer coatings and external temperature on fiber temperature was discussed.The upper limits of the pump power of different backward combiners were compared experimentally.The experimental results indicate that the(6+1)×1 triple-cladding backward combiner with a lower power ratio in the second cladding has a higher pump power upper limit than the(9+1)×1 combiner,which agree with the simulation results.A triple-cladding fiber laser is constructed with fully home-made devices,achieving an output power of 6.7 kW and a 3 dB linewidth of 0.32 nm.