High-spectra-resolution Mie Doppler lidar based on a two-stage Fabry-Perot etalon for tropospheric wind and aerosol accurate measurement

A two-stage Fabry-Perot etalon (FPE)-based high-spectral-resolution (HSR) Mie Doppler lidar technology is proposed that is capable of simultaneously detecting tropospheric wind and aerosol optical properties with high precision. The lidar structure is designed, and the measurement principle is analyzed. A two-channel integrated FPE forming a two-stage FPE ensures the relative stability of the spectra. The HSR first-stage etalon can effectively suppress the contamination of Rayleigh signal. The transmission and reflection spectra of the second-stage etalon can form a double edge (DE) to measure wind speed. Two multimode polarization-insensitive optical circulators are used to achieve high-efficiency utilization for backscattering signals. The parameters of the two-stage FPE are optimized. According to the selected system parameters, the detection performance of the proposed lidar is simulated. Simulation results show that with 150 m range resolution and 1 min total accumulation time for the paired line-of-sight (LOS) measurement, within +/- 25 m/s LOS wind speed range, the nighttime and daytime LOS wind speed errors are below 0.48 m/s and 2.5 m/s, respectively, for a clear day, and below 0.58 m/s and 5.5 m/s, respectively, for a hazy day from 0.1 km to 8 km altitude; the backscatter ratio relative errors are below 2.7% up to 8 km for a clear day, and below 4.6% up to 5 km for a hazy day. Compared with the traditional dual-FPE-based DE Mie Doppler lidar, the wind speed accuracies are improved by 2.02-3.58 times for a dear day and 2.14-4.31 times for a hazy day. (C) 2019 Optical Society of America