【摘要】 望远镜接收的后向散射光场与单模光纤的耦合效率是影响全光纤拉曼测温激光雷达系统性能的重要参数之一。通过分析自由空间平面光场与单模光纤耦合的数学模型,阐明了同轴激光雷达接收望远镜中心遮挡对最佳耦合效率的影响,并对不同遮挡率时横向偏移、倾斜角度和离焦误差等安装误差对耦合效率的影响进行数值分析。然后以此为基础采用Zemax软件创建望远镜耦合系统优化设计的初始光学系统,增加并选择合适的透镜和微透镜及优化系统结构参数,使系统在遮挡率为0.288时总耦合效率从卡塞格林望远镜直接耦合的17%提高至50%。最后提供了两种微透镜阵列与单模光纤阵列结构来提高光信号耦合能量。结果表明,使用微透镜阵列与单模光纤阵列耦合的新型望远镜耦合系统可以提高拉曼激光雷达系统的耦合效率和能量。更多还原

【Abstract】 The coupling efficiency of the backscattering optical field received by the telescope into single-mode fiber is one of the significant parameters affecting all-fiber Raman lidar system.By analyzing the mathematical model of coupling the free space plane optical field into single-mode fiber,the influence of the telescope central obstacle in the coaxial lidar on the optimum coupling efficiency is clarified.And then it is numerically analyzed the change of the coupling efficiency with the variation of the alignment errors such as the lateral offset,tilt angle and defocus error with different obstacle ratios.Furthermore,based on these conclusions,an initial optical system is constructed for the telescope coupling system optimization.By adding and choosing suitable lenses and micro lenses and optimizing the configuration parameters,the total coupling efficiency of 17% with the Cassegrain telescope is enhanced to 50% when the obstacle ratio is 0.288.Two coupling configurations with micro lens arrays and fiber arrays are designed to improve the coupling energy of light signal.Simulation results show that the coupling efficiency and energy may be improved using the new telescope coupling system with micro lens array and single-mode fiber array.更多还原