Digital demodulation algorithm for white-light fiber optic interferometric sensors

Abstract

New digital demodulation algorithm for white-light interferometric sensors with signal processing in spectral domain is presented. The algorithm uses phase calculation from an interferometric pattern in the acquired spectrum from the sensor to evaluate the optical path difference. Suggested demodulation method provides high accuracy with uncertainty close to theoretical limit imposed by system noise. For a fiber-optic sensor with birefringent fiber and a CCD spectrometer for signal acquisition, the algorithm demonstrated the random error of the optical path difference estimate about 0.18 nm.