An Optimization Method of Local Oscillating Beam Power for Coherent Wind Lidar

The working principle and the influence factors of carrier-to-noise ratio of heterodyne detection are analyzed in this paper. The local oscillating beam power optimization method is proposed based on the saturation effect of photoelectric detector. Increasing the local oscillating beam power, the transpose gain can be increased, and then the detection limit of carrier-to-noise ratio can be reached. Too high local oscillating beam power will affect the precision of the photoelectric detector, then the photoelectric detector works in the nonlinear region, therefor the carrier-to-noise ratio is reduced. In this paper, the optimization strategy of carrier-to-noise ratio is proposed via analyzing the relationships between the heterodyne signal and the local oscillating beam power, the noise and the local oscillating beam power. The experimental results show that the optimal power of the local oscillating beam can be obtained for different working wavelengths of local oscillating beam by the optimization method proposed.