在利用正弦相位调制菲佐干涉仪进行测量时,由于菲佐板及待测物体表面对入射光的多次反射而产生多光束干涉,干涉信号的强度随相位变化不是严格的余弦分布。按照双光束干涉的算法进行相位信息提取,会引入一定的误差。以正弦相位调制菲佐干涉仪纳米精度微小位移测量为应用背景,分析多光束干涉情况下该干涉仪信号解调算法的误差,进而对干涉仪的相关参数进行优化,并通过误差补偿对测量结果进行修正,有效减小了多光束干涉产生的影响。 When using the sinusoidal phase modulation Fizo interferometer to measure, the multi-beam interference occurs due to the multiple reflection of the incident light on the surface of the Fischer plate and the object to be measured. The intensity of the interference signal changes with the phase and is not a strict cosine distribution. According to the algorithm of two-beam interference, phase information extraction, will introduce some error. In this paper, the error of demodulation algorithm of interferometer signal under multi-beam interference is analyzed with the application of sinusoidal phase-modulated Fischer interferometer with small displacement of nanometer precision. Then the relevant parameters of the interferometer are optimized, and the error of compensation Be amended, effectively reducing the impact of multi-beam interference.