Patent ID: 6836334
Filing Date: 2004-12-28
Classification: G01C

Abstract:
A method for reducing noise in a fiber optic sensor comprising an optical source providing optical power to a sensing coil through an optical fiber and a first coupler positioned between the optical source and the sensing coil to direct a sensor signal from the sensing coil to a photodetector, the method comprising:(a) providing an optical amplifier between the first coupler and the photodetector; (b) providing an isolator between the first coupler and the optical amplifier to suppress back facet emissions of the optical amplifier; (c) providing a second coupler between the optical amplifier and the isolator; (d) providing a second detector on a leg of the second coupler to receive the back facet emissions from the optical amplifier; and (e) subtracting the back facet emissions received at the second detector from the sensor signal and front facet emissions of the optical amplifier received at the photodetector.