为了避免高功率光纤激光器中光纤端面出现热效应问题, 依据多点级联结构的耦合器, 对分布式抽运的光纤激光器进行了研究。首先, 介绍了实验室自主研制的级联耦合器。然后, 分析了耦合器插入对光纤激光器的影响。最后, 选用自制的耦合器搭建了分布式抽运的光纤激光器。实验结果表明: 对耦合器插入损耗的研究, 能够促进高功率级联耦合器的实现。在光纤激光器结构中, 975 nm泵浦功率注入1.1 kW时, 1 080 nm激光功率输出为770 W, 光-光转换效率为77%。在主控振荡功率放大结构中, 激光功率输出为635 W, 放大级的光-光转换效率为78%。分布式抽运方式可以使泵浦光多点注入, 避免了热量的集中, 能够获得千瓦级的激光功率输出。

In order to avoid the thermal effect of fiber-end in high power fiber laser, the fiber laser based on the multi-point cascaded was studied. First, the self-developed cascaded couplers were introduced. Then, the effect of the couplers insertion on the fiber laser was analyzed. Finally, the fiber laser and the master oscillator amplifier with the pumping distributed structure were built. Experimental results indicate that the research on the insertion loss of the coupler can promote the development of high power cascaded coupler. In the distributed fiber laser, the output power of 1 080 nm is 770 W with the pump power of 1.1 kW, and the optical to optical conversion efficiency is 77%. The output power of maser oscillator power amplifier structure is 635 W with the optical conversion efficiency is 78%. It can satisfy that the distributed pumping can solve the heat concentration in fiber laser, can achieve the kilowatt fiber lasers.