Application and analysis of the dual Fabry-Perot etalon in a direct detection wind lidar

A direct detection Doppler wind lidar with the dual Fabry-Perot technique has been built and the system is described. The dual etalon with high-spectral resolution is used to discriminate the Doppler shift by the aerosol backscattering. Analysis shows that the etalon transmittance is affected by the beam divergence. The stability of the dual etalon is also analyzed and the result shows the system is steady in 100 min. The transmittance curve of the dual etalon is measured, which indicates that the error in the velocity dynamic range is less than 0.6 m/s for heights up to 5 km and the error increases with the large radial velocity and decreases with pulse number increasing.