Four step discrete phase shift demodulation method for fiber optic sensor arrays

摘要

A sinusoidal phase generated carrier is used to demodulate signal output from an interferometric sensor array. Optical signals input to the array are modulated with a sinusoid. Output signals are sampled and integrated over portions of a period of the phase generated carrier. A key to this method of sampling is the existence of pairs of signals associated with integration over two 180 DEG out-of-phase portions of the phase generated carrier. This invention is a four step method involves the implementation of two pairs of such signals to determine the phase shift in each sensor in the array.