正弦相位调制自混合干涉微位移测量精度分析

为了提高自混合干涉仪的位移测量精度,提出将正弦相位调制技术引入自混合干涉中。相位调制由置于自混合干涉仪外腔中的电光晶体实现,相位解调由傅里叶分析的方法得到。对位移测量过程中各种可能的误差来源如电光晶体调制不稳定性、光在外腔中的二次反馈效应等对测量精度的影响进行了模拟分析,从理论上得到了这种新的信号处理方法可以达到纳米级的测量精度。实验上,用高精度的商用压电陶瓷标定的结果验证了这种正弦相位调制自混合干涉仪在普通实验室噪声环境中可以达到纳米级的位移测量精度。

Analysis of Micro-Displacement Measurement Accuracy in Self-Mixing Interferometer Based on Sinusoidal Phase Modulating Technique

Sinusoidal phase modulating technique is introduced in to the self-mixing interference in order to improve the displacement measurement accuracy of the self-mixing interferometer.Phase modulation is obtained by an electro-optic crystal in the external cavity and phase demodulation is achieved by Fourier analysis method.Error sources that can influence the displacement measurement accuracy such as modulating instability of the electro-optic crystal(EOM) and the multiple feedbacks effect in the external cavity have been simulated and the measurement accuracy of the new signal processing method is obtained theoretically.Experimentally,calibration results with a high precision commercial PZT show that a displacement measurement accuracy of nanometers scale is achieved in the common laboratorial environment.