Accession Number : ADD009066

Title :   Method for Suppressing Thermally Induced Signals in Fiber Optic Interferometric Sensors.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Priest,Richard G

Report Date : 31 Aug 1981

Pagination or Media Count : 10

Abstract : A method and apparatus is described for providing an improved Mach - Zehnder interferometer type optical fiber acoustic sensor wherein spurious environmentally induced signals are separated from the sensor output and fed back into the system in a manner to cancel their effect. Both true and spurious acoustic signals cause a phase shift in light passing through a sensing arm of a Mach-Zehnder interferometer. Error signals, corresponding to the frequency of the spurious signals, are selected from the interferometer output, processed, and fed back into the interferometer output, processed, and fed back into the interferometer reference arm in a manner to cause a phase shift therein just sufficient to cancel the effect of the initial spurious acoustic signal, whereby the interferometer is locked in phase and held quadrature condition such that the output signal represents the true (desired) signal.

Descriptors :   *Patent applications, *Optical interferometers, *Compensation, *Spurious effects, Acoustooptics, Coupling(Interaction), Phase shift, Feedback, Acoustic signals, Fiber optics, Errors, High sensitivity, Noise reduction

Subject Categories : Fiber Optics and Integrated Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE