大口径端泵片状放大器的泵浦耦合系统

摘要

A coupling system with a high contraction coefficient, up to 86∶1, has been designed and manufactured.The output from the spherically arranged 80 kW LD arrays is delivered by orthogonal cylindrical lenses and a hollow duct.Experimentally measured coupling efficiency of the system is 84.2%.Intensity modulation values of the pump-field at the exit are 1.30 of LD fast axis and 1.18 of LD slow axis.The pump light can transport a distance of 8.5 mm at least with its shape preserved.The coupling system can meet the requirements of end-pumped slab amplifiers for high pump power and pump power density.%为了满足片状激光放大器对泵浦功率密度的要求,设计并加工了高缩束比的耦合系统.根据LD的发光特性,将输出功率为80 kW的LD阵列进行拟球面排列,采用正交柱面透镜配合空心导光管进行泵浦耦合,将发光面积为330 mm×85 mm的泵浦光,在输出口处压缩至18 mm×18 mm的口径,耦合系统的缩束比高达86∶1.模拟计算表明,该耦合系统的耦合效率对导光管反射板的反射率依赖性较低.实验测量该耦合系统的效率为84.2%,输出口处泵浦光场快慢轴的调制度分别为1.30和1.18,且脱离耦合系统后的泵浦光传输8.5 mm后,依然可以保持泵浦光场的轮廓.该耦合系统在效率、泵浦场均匀性、传输性等方面均满足端面泵浦的片状放大器对泵浦耦合系统的要求.