THEORETICAL STUDY OF THE THERMAL DISTRIBUTION IN YB-DOPED DOUBLE-CLAD FIBER LASER BY CONSIDERING DIFFERENT HEAT SOURCES

Thermal effects limit the gain, quality, and stability of high power fiber lasers and amplifiers. In this paper, different values of heat conductive coefficients at the core, the first and second clad with the complete form of the heat transfer equation are considered. A quartic equation was proposed to determine the temperature at the fiber laser surface. Using the surface temperature value, the temperature can be determined at the longitudinal and radial position of the double clad fiber laser. The different definitions of heat sources which were previously presented in articles is used to describe the heat generation at a double clad high pump power fiber laser condition. The results were compared to each other, and the percentage of each factor in heat generation was calculated.