自混合干涉效应在位移测量中的应用现状

An Overview of self-mixing interference applications in displacement measurement

本文对自混合干涉系统在位移测量中的应用情况进行了综述。首先对自混合干涉的发展概况进行介绍,然后重点介绍基于自混合干涉理论的位移测量方法。文中介绍的方法有条纹计数法、电流调制光频法、正弦相位调制法。条纹计数法最易于实现,但是分辨率低,一般为半个光波长。电流调制光频法提高了测量的精度,分辨率可以达到nm量级。正弦相位调制法利用外腔光路中的电光晶体对激光器功率相位进行调制,利用傅里叶变换解调出相位,具有很高的测量精度,可用于微位移的测量。

In this paper,applications of the self-mixing interference system in displacement mea-surement are reviewed. After introducing the development of the self-mixing interference,we focus on the displacement measurement methods based on the self-mixing interference theory. The fringe count-ing method,current modulation optical frequency method and the sinusoidal phase modulation method are introduced. Fringe counting method process is easy to implement,but the distinguishability is low, which is the half of a wavelength of light. Current modulation optical frequency method improves the measurement accuracy,with the distinguishability up to nanometer. Sinusoidal phase modulation method uses the electro-optic crystal in external cavity optical path to modulate the phase of laser power,and then the phase will be demodulated by Fourier transform. This method has a very high measuring accu-racy and can be used for micro-displacement measurement.