Influence of photocurrent noise on detection performance of continuous coherent lidar

Abstract

In order to study the influence of photocurrent noise on the detection performance of continuous coherent lidar, the waveform of photocurrent spectrum and the problem of lidar noise are studied theoretically and experimentally. When the optical beam is split after the optical fiber amplifier and the wind measurement experiment is carried out, the “crosstalk” is small, the signal-to-noise ratio of the system is high, and the echo data can be effectively obtained; however, the “crosstalk” is large and the signal-to-noise ratio of the system is low when the beam is split after the seed laser and the wind measurement experiment is carried out, so the effective echo data cannot be obtained. According to the research results, a set of nacelle lidar with beam splitting after the optical amplifier was developed. It was installed in the wind farm and tested in the field. The lidar can achieve 86% data acquisition rate. The experimental results show that the beam splitting at different positions affects the delay distance between the signal reflected by the circulator and the local oscillator light, thus affects the magnitude of the photocurrent in the system, and ultimately affects the detection performance of coherent lidar.