自混合干涉信号的幅度和波形均会随外腔静态长度发生周期性变化。实验测量了干涉信号幅度和波形随外腔静态长度的变化,并用多模自混合干涉信号叠加的方法计算分析了干涉信号的幅度随外腔静态长度的变化,然后考虑反馈光对内腔反射率和激光介质增益的影响计算分析了干涉信号的波形随外腔静态长度的变化。结果表明,多模激光自混合干涉信号随外腔静态长度变化的周期为内腔的光学长度,而其主极大区域的宽度为激光的相干长度,小于内腔的光学长度。多纵模自混合干涉信号的叠加导致自混合干涉信号的幅度随外腔静态长度发生周期性变化,而波形随外腔静态长度周期性变化则是内腔反射率和激光介质增益均受反馈光影响导致的非线性的结果。 The amplitude and waveform of the self-mixing interference signal periodically change with the static length of the external cavity. The variation of the amplitude and the waveform of the interferometer signal with the static length of the external cavity was measured experimentally, and the variation of the amplitude of the interfering signal with the static length of the external cavity was calculated by the method of multimode self-mixing interference signal superimposed. Then, And the influence of the gain of the laser medium The variation of the waveform of the interference signal with the static length of the external cavity is calculated and analyzed. The results show that the period of multimode laser self - mixing interference signal changes with the static length of the external cavity is the optical length of the cavity, while the width of the main maximum area is the coherence length of the laser, which is smaller than the optical length of the cavity. The superposition of multi-longitudinal mode self-mixing interference signals causes the amplitude of the self-mixing interference signal to change periodically with the static length of the external cavity. The periodic variation of the waveform with the static length of the external cavity is the feedback of lumen reflectivity and laser medium gain The resulting non-linear results.