Suppression of crosstalk in coding CDWL by active FOV modulation with a deformable mirror

Abstract

Coding technology provides new ideas for spatial resolution enhancement of coherent Doppler wind lidar (CDWL). To improve the performance of coding CDWL for ultra-fine-wind field detection, the crosstalk between neighboring laser pulses is analyzed in theory. The strong backscattered signal from aerosols in near field region will interfere with the weak atmospheric signal, making the accuracy of Doppler shift estimation deteriorate seriously. Considering the formation mechanism of crosstalk, a solution based on adaptive field of view (FOV) modulation is proposed to suppress the crosstalk which is validated by numerical simulation and experiment. Dynamic range of the backscatter intensity is controlled from 10 dB to 2 dB within the distance of 50 m to 300 m, thus the crosstalk is accordingly suppressed.