Opto-thermal coupling analysis and thermal management of high-power cladding power strippers

The thermal stability of high-power cladding power strippers (CPSs) is a critical bottleneck for fiber laser systems. The internal scattered light forms a unique, non-uniform interfacial heat source that is difficult to manage using conventional simplified thermal models. Taking the distributed optical scattering characteristics as the driving input, what we believe to be a novel self-adaptive hybrid relaxation algorithm is proposed to establish a multi-level coupled analysis framework. Furthermore, according to the thermal-flow coupling effect, the thermal-fluid behavior of a U-shaped water-cooled package structure is characterized comprehensively. To verify the accuracy of the analytical model, the temperature of the CPS under cladding-coupled input is measured experimentally. The study reveals the direct correlation between optical energy deposition and local temperature peaks. The results indicate that the optimized cooling system effectively controls the maximum package temperature to below 55°C, ensuring the device operates safely below the coating damage threshold under conditions ranging from low power (138.4 W) to high power (2171 W).