基于自混合现象的新型干涉技术, 由于其结构简单、低成本的优点, 目前在位移、速度、振动、距离等测量领域得到广泛应用。采用边发射半导体激光器作为激光 自混合速度测量系统的激光光源, 针对不同表面类型、采样时间、注入电流、信号处理系统对自混合 测速结果的影响进行实验研究和讨论分析。结果表明不同反馈和采样时间 (0.1 s, 1 s) 均能满足高 精度测速要求。同时, 实验中采用合适的激光工作电流 (激光器阈值电流1.1倍以上) 并结合零点控制 技术能够获得信噪比更大激光自混合测速信号。这些结论对深入分析自混合信号的产生机理以及半导体 激光自混合测量系统的优化具有参考意义。

Laser interferometry based on self-mixing effect is widely used to measure displacement, velocity, vibration and distance due to compactness, robustness, as well as low cost. Self-mixing interference produced by the feedback of light from a moved target into an edge emitting laser (EEL) was experimentally investigated for sensing applications. The self-mixing velocimeter with different types of surface, values of sample time and injection current, signal process system are also discussed. The results indicate that high precision requirement can be reached with different types of surface, values of sample time 0.1 s, 1 s. Experimental results of the self-mixing velocity measurement system show that selecting proper injection current (above 1.1 times of threshold current) of EEL and null control technique can enhance signal to noise ratio (SNR) of self-mixing signal. This conclusion can help to improve the mechanism of self-mixing and optimize the self-mixing vibration measurement system.