Accession Number : ADD011674

Title :   Fiber Optic Sensors Operating at DC.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Rashleigh,S C

Report Date : 22 Jan 1985

Pagination or Media Count : 18

Abstract : Document describes a fiber optic sensor for detecting and/or measuring a physical quantity varying at any frequency from a maximum desired frequency down to zero frequency with minimum disturbance from environmentally induced perturbations. A first highly birefringent optical fiber is positioned longitudinally adjacent to a second equally birefringent fiber. Each fiber has orthogonally disposed fast and slow axes. The fibers are oriented such that their fast axes are perpendicular to each other. When subjected to stress caused by a physical quantity acting on the fibers through a transducer, the birefringence of each of the tow fibers is asymmetrical altered thereby rotating the states of polarization of coherent light signals passing through the two fibers in a common direction. Environmental perturbations symmetrically alter the birefringence of each of the fibers thereby rotating that states of polarization of the light signals in opposite directions. The states of polarization of the light signals emanating from the two fibers are detected and combined such that the changes due to the physical quantity enhance each other while the changes due to environmental perturbations are cancelled. (Author)

Descriptors :   *PATENTS, *INTERFEROMETERS, *OPTICAL DETECTORS, *FIBER OPTICS, *ACOUSTICS, BIREFRINGENCE, LASER BEAMS, ORIENTATION(DIRECTION), ROTATION, COHERENT OPTICAL RADIATION, POLARIZATION, SIGNAL LIGHTS, ORTHOGONALITY, PERTURBATIONS, PHYSICAL PROPERTIES, ENVIRONMENTS, CANCELLATION, QUANTITY, AUGMENTATION, FIBERS, AXES, TRANSDUCERS, DETECTORS, PERTURBATIONS

Subject Categories : Lasers and Masers
      Test Facilities, Equipment and Methods
      Optical Detection and Detectors
      Acoustics
      Fiber Optics and Integrated Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE