Accession Number : ADD011689

Title :   Fiber Optic Gyroscope with Alternating Output Signal.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Rashleigh,S C

Report Date : 01 Jan 1985

Pagination or Media Count : 11

Abstract : A Sagnac rotation sensing interferometer that uses a Mach-Zehnder interferometer to provide incident light beams that counter-propagate through an optical-fiber loop. The Sagnac interferometer operates at maximum sensitivity for zero rotation rates when the Mach-Zehnder is adjusted so that the intensities of the incident light beams are equal. By peiodically varying the position of a mirror in the Mach-Zehnder the interferometer is switched into and out of quadrature so that the amplitude of the interferometer output signal is modulated at frequency f sub o. Phase sensitive detection at 2F sub o or multiples thereof reduces the background noise level several orders of magnitude below the level for dc operation.

Descriptors :   *PATENTS, *INTERFEROMETERS, *GYROSCOPES, *FIBER OPTICS, *RING LASERS, PHASE DETECTORS, BACKGROUND NOISE, LEVEL(QUANTITY), ALTERNATING CURRENT, DIRECT CURRENT, OPERATION, SENSITIVITY, OUTPUT, DETECTION, NOISE, ROTATION, SIGNALS

Subject Categories : Lasers and Masers
      Fiber Optics and Integrated Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE