Design of a phase-shifting optical feedback interferometer using anelectrooptic modulator

摘要

A laser sensor using optical feedback interferometry has beenndesigned to measure displacements up to several micrometers. For thisnpurpose, a lithium niobate crystal generates a phase shift in order tonmodulate at a frequency of 580 kHz the optical path difference betweennthe sensor and the target. This setup has been calibrated by means of ancommercial optical fiber sensor. The overall accuracy resulting isnbetter than 65 nm for a 1-kHz sinusoidal motion of the target at 10 cmnaway from the sensor