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设计了一个半导体激光自混频干涉式测量物体振动速度的实验,利用双镜F_P(法布里_珀罗)等效模型,对半导体激光自混频干涉速度仪中的干涉效应进行了理论分析,推导了干涉信号理论模型的数学表达式,讨论了影响测量信号的因素。结果表明,在半导体激光自混频干涉速度仪的无源腔中空气密度的变化、无源腔长度的变化、激光波长的变化都将会导致信号漂移,从而引起测量误差。而被测物体表面的反射率越高,越有利于测量。
An experiment of self-mixing interferometric measurement of the vibration velocity of semiconductor laser was designed. By using the F_P (Fabry-Perot) equivalent model, the interference effect in the semiconductor laser self-mixing interferometer was analyzed theoretically , The mathematical expression of the theoretical model of the interference signal is deduced and the factors affecting the measurement signal are discussed. The results show that the change of air density, the change of the length of passive cavity and the change of laser wavelength will lead to the signal drift in the passive cavity of semiconductor laser self-mixing interference velocity meter, which leads to the measurement error. The higher the reflectivity of the surface of the measured object, the more conducive to measurement.