信号的不对称性是激光自混合干涉效应的重要特性之一，它提供了对物体运动方向的直接判别依据。利用双镜等效模型，对自混合干涉效应进行了理论分析，推导出干涉信号理论模型的数学表达式，阐述了信号不对称性形成的机理；仿真结果与已有的实验结论是一致的 The signal asymmetry is one of the important characteristics of the laser self-mixing interference effect, which provides a direct basis for determining the direction of motion of an object. Based on the double-mirror equivalent model, the self-mixing interference effect is theoretically analyzed, the mathematical expression of the theoretical model of the interference signal is deduced, and the mechanism of signal asymmetry is expounded. The simulation results are consistent with the existing experimental results