为了研究合束效率与二向色镜的反射性质之间的关系,通过建立多层膜系粗糙表面反射模型,采用模拟仿真的方法对用于光谱合束的大陡度二向色镜反射率曲线进行了计算分析,结合光纤激光器光谱曲线得到了合束效率的仿真结果。对不同角度二向色镜表面面形与反射率、合束效率的关系进行了分析,对二向色镜合束系统的稳定性进行了模拟讨论,并对二向色镜的部分参量提出了要求。结果表明,使用小角度二向色镜可以获得10kW以上的输出功率,合束效率达97%。这一结果对二向色镜参量的提高是有帮助的。

In order to study the important relationship between combining efficiency and reflectivity of dichroic mirrors, rough surface reflection model of multilayer coatings was established. Reflective curves of high-steepness dichroic mirrors for spectral beam combining were calculated and analyzed. Simulation results of combining efficiency were obtained by combining the spectral curves of fiber lasers. The relationship between the surface shape of dichroic mirrors with different angles and reflectivity and combining efficiency were analyzed. The stability of the beam combining system based on dichroic mirrors was simulated and discussed. The results show that, output power of more than 10kW can be obtained by using a small angle dichroic mirror, and combining efficiency can reach 97%. This result is helpful for the improvement of the parameters of dichroic mirrors.