Huang Long, Wu Hanshuo, Li Ruixian, Li Lei, Ma Pengfei, Wang Xiaolin, Leng Jinyong, Zhou Pu
Opt Lett. 2017 Jan 1;42(1):1-4. doi: 10.1364/OL.42.000001.
A high-power 1064 nm single-frequency polarization-maintained fiber amplifier based on an all-fiber master oscillator power amplifier configuration is demonstrated. To mitigate the stimulated Brillouin scattering (SBS) and the mode instability (MI) effect, a polarization-maintained Yb-doped fiber with a high dopant concentration and a 25 μm core diameter is adopted in the main amplifier stage; in addition, step-distributed longitudinal strain is imposed on the active fiber to broaden its effective SBS gain spectrum and further increase the SBS threshold. As a result, a pump-limited 414 W single-frequency fiber laser is obtained without signs of SBS and MI. Experimental results show that the SBS threshold is increased by at least two times. The slope efficiency of the main amplifier is about 80%. The polarization degree is higher than 98% at all the power levels. The beam quality is measured with a M of 1.34. To the best of our knowledge, this is the highest output power of single-frequency polarization-maintained fiber amplifier based on an all-fiber structure.
展示了一种基于全光纤主振荡功率放大器配置的高功率1064 nm单频保偏光纤放大器。为了减轻受激布里渊散射（SBS）和模式不稳定性（MI）效应，在主放大器阶段采用了具有高掺杂浓度和25μm芯径的保偏掺镱光纤；此外，对有源光纤施加阶跃分布的纵向应变，以拓宽其有效SBS增益谱并进一步提高SBS阈值。结果，获得了泵浦受限的414 W单频光纤激光器，且没有SBS和MI的迹象。实验结果表明，SBS阈值提高了至少两倍。主放大器的斜率效率约为80%。在所有功率水平下，偏振度均高于98%。用M²为1.34测量了光束质量。据我们所知，这是基于全光纤结构的单频保偏光纤放大器的最高输出功率。
