The Thermal Stress Analysis Of Double-cladding Planar Waveguide Lasers

This thesis is supported by the National Science Fundation Council of China under the project "Research of double-cladding waveguide lasers with direct bonding technology (No. 60578222)."Recently, the maximum optical-electric conversion efficiency has come up to 70%, and the high-power laser diode arrays (LDs) have become more and more attractive. As an ideal pump source, it promotes the development of the high-power lasers.In the high-power LDs pumping lasers, the laser medium ,in which causes a nonuniform temperature in the high-power solid-state laser, is the key problem which leads to serious thermal effect. The direct result of this problem is to decrease the qualityof laser beam and even to make laser crystal break up. Thermal effects have become the serious obstacles to improve laser power further.So in order to improve the laser beam quality and output power, the laser medium in small size could be used to reduce the thermal effects, and the effective thermal effect of compensation is considered. Based on this background, this paper mainly focus on the following as:(1) Nd: YAG solid-state lasers development process and the status quo, the status of laser medium thermal analysis and the advantage of reducing thermal effect with double-clad planar waveguide lasers were introduced.(2) The thermal source model of end-pumped double-clad planar waveguide laser medium was analyzed.(3) The analytical solutions of temperature field and thermal stress field in the gain medium of simple laser structure were analyzed based on both theoretic method and the finite element method, to make sure the correctness and accurary of the finite element method.(4) Based on two-dimensional model, theoretical analysis and numerical simulation were focus on the thermal effect of bi-directionally end-pumped double-clad planar waveguide lasers. Factors which could impact the thermal stress of double-clad planar waveguide laser medium were researched. Further enhance the quality of laser, increasing laser power output are provided.