2-FREQUENCY FIBEROPTIC SENSOR SYSTEM USING HIGH-BIREFRINGENCE OPTICAL FIBER

Abstract

A fiber sensor system based on high-birefringence optical fiber and a frequency-stabilized He-Ne Zeeman laser (lambda = 0.6328-mu-m) has been demonstrated. The small path-length changes of interest are extracted from the amplitude or phase of the laser beat frequency by using either the phase-sensitive detection or the phase-demodulation technique. A minimum detectable optical phase delay of 1.5 x 10(-6) rad/Hz1/2 or 17 x 10(-6) rad/Hz1/2 has been achieved.