双包层光纤涂覆层的热损伤是高功率连续光纤激光器运转的主要限制因素之一。对高功率连续光纤激光器中的热效应进行研究，并对于仅由于涂覆层的热损伤引起的功率极限给出了理论模拟。进行了千瓦级光纤激光器中无源光纤与增益光纤熔点冷却的理论与实验研究。对于不同的冷却结构分别测量光纤与热沉之间的热接触电阻，并提供了有效的散热方案实现热量的有效传导。采用新型散热技术，基于主振荡功率放大（MOPA）结构，研制出1080 nm 1.11 kW全光纤激光器样机。放大级抽运光注入处熔点表面最大温度为327 K（54 ℃），运行过程中没有非线性效应和热损伤现象出现。

Double-clading fiber coating thermal damage is one of the prime limiting factors for the operation of high-power continuous-wave (CW) fiber lasers. The thermal effects in high power CW fiber lasers are studied, and the maximum output power of fiber lasers limited by the thermal degradation of coatings is theoretically simulated. Theoretical and experimental studies of splice points cooling in 1 kW CW fiber lasers are presented. Thermal contact resistances between the fiber and its heat sink are measured separately for different geometries and efficient cooling methods to achieve effective heat conduction are proposed. By using these optimized methods, based on the master oscillator power amplifier (MOPA) architecture, a 1080 nm 1.11 kW all-fiber laser prototype is obtained. The maximum surface temperature at the pump light launching end splice of the booster amplifier is 327 K (54 ℃). Moreover, thermal or nonlinear effects have not been observed during operation.