半导体激光器自混合振动系统优化研究

Optimization of the laser vibrometer based on the self-mixing effect in a diode laser

为了优化半导体激光自混合振动测量系统,本文采用三镜腔理论模型,结合激光自混合振动测量的实验结果,利用数值模拟的方法对激光自混合振动信号进行仿真分析,获得了不同外腔耦合系数ζ(0.25×10-4～1.75×10-4)以及不同半导体激光器(LD)线宽展宽因子α(1～5)下自混合振动测量信号的时域特性。结果表明,较大的外腔耦合效率ζ和LD线宽展宽因子α能够获得信噪比更大、方向性更好的激光自混合振动波形。

In order to optimize the self-mixing interference,a theoretical analysis on the self-mixing interference is presented by using a three-mirror cavity model to optimize the self-mixing vibration measurement system.Combining with the experimental results of the self-mixing vibration measurement system,the time domain characteristics of self-mixing signal are obtained corresponding to the external cavity coupling efficient ζ parameter from 0.25×10-4 to 1.75×10-4 and the linewidth enhancement factor parameter α from 1 to 5.The results indicate that larger external feedback strength and linewidth enhancement factor of laser diode（LD） can enhance signal to noise ratio（SNR） and in favor of direction discrimination.