光电探测器非线性响应对相干激光多普勒测速仪的影响

光电探测器是相干激光多普勒测速仪的重要组成部分，其对光信号强度的响应特性直接影响着系统的信噪比。为了提高系统探测性能，从光电探测器非线性响应对相干激光多普勒测速仪的影响的角度进行研究。通过对响应函数进行多项式分析，研究输入拍频信号为带偏置的余弦信号时的输出电压波形，对比分析存在二阶非线性响应与在线性响应下的信号，从理论上说明探测器非线性响应对系统信噪比的影响。并对测速仪进行了对比实验，在对非线性响应进行抑制之后，系统信噪比由16dB 提高到35dB，从实验角度验证了分析的正确性。

Impact of photodetector’s nonlinear response on coherent laser Doppler speedometer

Photodetector is an important part of coherent laser Doppler speedometer, and the optical intensity response of which has a great impact on the system's signal-to-noise ratio (SNR). In order to improve the detection performance, the impact of photodetector's nonlinear response on the laser Doppler speedometer was studied. The response function was deduced by using polynomial analysis. The output voltage waveform under nonlinear response was compared with that under linear response, theoretically demonstrating the impact of photodetector's nonlinear response on the SNR of the system. Comparison experiments indicate that through the suppression of the nonlinear response, the SNR raises from 16 dB to 35 dB, which results in the correction of the analysis.