双边缘技术多普勒测风激光雷达标准具的优化

Optimization of etalon parameters in direct detection Doppler wind lidar

优化了基于双边缘技术的直接测风多普勒激光雷达中F-P标准具的工作参数。确定激光谱宽后,选择适当的F-P标准具自由谱间距,可正确消除瑞利背景噪声的影响。分析了标准具镜面缺陷、非严格平行和入射光束发散角对其透过率曲线的影响。将标准具透过率函数表达为唯一系统参数,即反射精细度的函数;通过计算散粒噪声极限时的相对测量误差,可确定最优反射精细度以及激光频率相对标准具透过率中心频率的最佳偏置;由最优反射精细度可得到入射到标准具光束的最大发散角和标准具的最小通光口径。

Based on double-edge technique, the optimization of the operation parameters of Fabry-Perot interferometers in the direct detection Doppler wind lidar is presented. The effects of the laser spectral width, mirror surface defects, parallelism errors, beam divergence of illumination on the transmittance of the etalon are considered. By convolution method, the Fabry-Perot interferometer transmittance function With different spectral broadening defect is given. The free spectrum range is chosen to subtract the Rayleigh signal from the atmospheric back-scattering correctly. The transmittance of aerosol back-scatter signal through the interferometer is expressed as a function of the reflectance finesse, which is the unique system parameter. By considering the ratio of the measurement uncertainty to Cramer-Rao lower bound uncertainty under condition of the signal shot-noise limit, the optimal reflectance finesse and the frequency offset between the outgoing laser and the center transmittance, the center frequency of Fabry-Perot interferometer can be determined. By giving the optimum reflectance finesse, the maximum beam divergence and minimum aperture of the Fabry-Perot interferometer can be obtained.