A Synchronous Phase-Detection System for an Optical Interferometric Sensor

Abstract

(Continue on reveree tide If neceeeary and Identify by block number)A system has been developed to accurately detect phase produced in optical interf erometric sensors. The system employs optical heterodyning, and it synchronously detects optical phase by feeding an error signal back to a phase modulator in the reference leg of the interferometer. This system is seen to have properties similar to a phase-locked loop used for the demodulation of FM signals. The system model is second order and nonlinear, but a linear approximation serves to accurately describe the system in synchronous operation and (over)