Research on the LD side pumping field of solid-state lasers

Solid-state lasers are widely used in many applications. The LD pumping module is the power source of the laser system. A well-designed pumping light field can achieve high efficiency and high quality laser output. In this paper, a mathematic model of the side-pumping module is constructed. The light field of a single LD bar is tested and simulated with different parameters with the ray tracing method. Then the pump power distribution in the cross section of the LD array is analyzed, which indicates the absorption and distribution in the laser rod. An improved method by increasing the pumping sides is proposed to achieve higher pumping homogeneity. Simulation results show that the pumping homogeneity is improved. A pumping module is produced according to the design. After a small adjustment of the mathematic model, the test result of the rod cross section photos fits the simulation well. Then an optical resonant cavity with a Nd: YAG laser rod is set up. The laser with the beam quality near the diffraction limit is obtained. The LD pumping module can be used in high power MOPA laser systems. The improved mathematic model can be used to simulate and design side-pumped lasers in future.