Design And Implementation Of High Power Side Pumped Laser Module

In recent years,as the core device of diode pump solid state laser(DPSSL),the diode-side-pumped module suffers from two serious problems: one is difficult to couple efficiently pump light,and another is difficult to eliminate the redundancy heat in the crystal.Above problems lead to some difficulties for obtaining high power and high beam quality in DPSSL.In response to the above-mentioned problems,this thesis has carried out the design and experimental research for high-power diode-side-pumped module.The purpose is to obtain a diode-side-pumped module with compact structure,high power,high coupling efficiency and near-fundamental laser output.The research has important application value and research significance for improving the DPSSL performance.The main content and innovation of this thesis are as follows.1.In this thesis,the status of DPSSL at home and abroad is described in detail,and two key problems of diode-side-pumped module in DPSSL are discussed.On the one hand,the existing pumping methods and optical coupling structure are summarized,and on the other hand,these ways used to eliminate the redundant heat of crystal are analyzed in detail.According to the analysis results,it is found that:(1)Combining the direct close coupling and the physical coupling,which is a most suitable way for high-power diodeside-pumped modules.(2)Using of heat conduction cooling method can effectively eliminate the redundant heat in the crystal.2.The optical coupling structure in diode-side-pumped module is theoretically simulated by COMSOL software,and the influence of optical coupling structure parameters on the optical field distribution in the crystal also is analyzed,and uniform light field distribution is obtained.Then,all kinds of factors such as the heat dissipation efficiency and the physical parameters influence on the redundant thermal effect of the crystal are studied,and a theoretical simulation model about the cooling system of the diode-side-pumped module is constructed,and stable light field distribution of diode-side-pumped module on temperature are obtained.Based on the above theoretical simulation analysis and results,an optimized design scheme about the diode-side-pumped module also has been proposed.3.Based on the above-mentioned optical coupling structure and cooling system design scheme,the overall structure design of the diode-side-pumped module is completed,and the coupling effect of pump light is tested based on the completed side pump module.The coupling efficiency,which represents the performance of the optical coupling structure,is as high as 82.5%.Then,a flat-concave linear resonant cavity is constructed,and a lot of data relate to module are analyzed.The law between the cavity length and the output power is found,and the optimal value of the resonant cavity length is 270 mm.Finally,based on the flat-concave linear resonator,a 1064 nm band laser is built to carry out the experimental research on the output characteristics of laser side module.Experimental results show that,when the pump input power is 90 W,maximum output power,optical-to-optical conversion efficiency and beam quality factor is 21.6W,24% and 1.221 respectively.These results confirm that the designed diode-side-pumped module have reached the expected goal.