高功率双包层光纤激光器温度分布的有限元分析

高功率双包层光纤激光器的热效应严重制约光纤激光器的输出功率和光束质量。首先通过求解热传导方程得到简化情况下的温度解析解;然后，利用有限元方法对不同情况下的温度分布进行模拟计算。通过模拟计算得到：外包层聚合物材料的热传导系数对光纤的温度分布影响较小，因而在近似计算时可以认为纤芯及内、外包层热传导系数相等;外包层表面的对流换热系数对温度分布影响较大，增大对流换热系数，可以有效地降低光纤激光器的热效应;外包层光纤半径的大小对光纤激光器的温度分布也有影响。所得的结果为设计实现千瓦级光纤激光器提供了参考。

Finite Element Analysis of Temperature Distribution of High Power Double-Cladding Fiber Laser

Thermal effects of high power double-cladding fiber laser severely limit the output power and beam quality. Firstly, temperature distribution in high power double-cladding fiber laser was analyzed by thermal conductive equation. Secondly, temperature distribution was simulated by finite element methods, at different conditions. Results indicate that temperature distribution was hardly affected by thermal conductivity of polymer cladding materials, so, when calculating the heat transfer coefficient of the core, the first and the second cladding can be seen as identical; the temperature distribution was great affected by heat transfer coefficient of cladding surface, increasing the heat transfer coefficient can reduce the thermal effects of fiber laser; the cladding's radius also can affect the temperature distribution. Conclusions are useful for designing kW level fiber laser.