A heterodyne interferometer using an electro-optic modulator for measuring small displacements

Abstract

In this heterodyne interferometer for measuring small displacements, an electro-optic modulator is used as a frequency shifter. It has some merits, such as, free from the mechanical vibration, simple and compact optical structure, and a general and inexpensive electrical signal processing circuit can be used without decreasing the measuring resolution and easily operated in real time.