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对激光自混合干涉式位移测量原理进行了数值模拟和实验研究。首先,从三镜法布里-珀罗腔理论出发,得到了基于半导体激光自混合干涉原理的位移测量模型,在此基础上对多种波形调制外反射体位移情况下激光自混合干涉信号进行了理论分析,证实信号倾斜方向发生反转的间隔条纹数目对应反射体位移的幅值范围;反射体有半个波长的位移,信号即输出一个完整的条纹;反馈强度的增加将增大输出条纹的倾斜。对信号倾斜现象进一步分析发现,当反射体位移减小时,信号向左倾斜,反之向右。造成信号倾斜的原因是由于高反馈强度下引起的非线性相位调制了输出信号强度。这些结论同样适用于任意波形调制的反射体位移。实验测试结果同理论分析吻合较好。
The self-mixing interferometric displacement measurement principle of laser was numerically simulated and experimentally studied. First of all, based on the three-mirror Fabry-Perot cavity theory, a displacement measurement model based on semiconductor laser self-mixing interference principle is obtained. Based on this, the laser self-mixing interference signals The theoretical analysis shows that the number of interval fringes reversing in the direction of signal inclination corresponds to the amplitude range of the reflector displacement. The reflector has a half-wavelength displacement and the signal outputs a complete fringe. The increase of the feedback intensity will increase the output fringes The tilt. Further analysis of the phenomenon of signal tilt found that when the displacement of the reflector decreases, the signal is tilted to the left and vice versa. The reason for the signal skew is that the output signal strength is modulated by the non-linear phase induced by the high feedback intensity. These conclusions also apply to reflector displacement of arbitrary waveform modulation. Experimental results agree well with the theoretical analysis.