WIDE BANDWIDTH FIBER OPTIC ACCELEROMETER

摘要

A vibration sensor (24) is disclosed which uses a piezoelectric crystal (26) to electrically modulate the phase of a laser beam using a phase modulator (28) producing a linearly phase modulated light beam. A DC bias can be provided by a battery (60) while a photocell (64) can provide the DC bias along with a calibration signal. The sensitivity of the sensor (24) can be doubled by passing the light beam through the sensor (24) twice using a reflector (74). By routing optical fibers (20, 22 and 31) carrying a reference beam and a sensing beam along the same physical path mechanical stress effect noise can be removed.