Method for Suppressing Thermally Induced Signals in Fiber Optic Interferometric Sensors.
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 31, 1981
- Accession Number
- ADD009066
Entities
People
- Richard G. Priest
Organizations
- United States Department of the Navy