Accession Number : ADD010703

Title :   Extended Fiber Optic Sensor Using Birefringent Fibers.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Taylor,H F

Report Date : 20 Sep 1983

Pagination or Media Count : 10

Abstract : An optical technique for detecting acoustic waves of selected frequency and determining their angle of arrival in a medium such as water. The technique utilizes one or more lengths of single mode optical fiber having a birefringence whose orthogonal axes are helically disposed throughout the length of the fiber at a predetermined uniform pitch. Sound pressure waves of certain frequencies incident upon the fiber throughout its length change its birefringence which affects the relative phase of polarized light components propagating from one end to the other by an amount proportional to amplitude of the acoustic wave. The twisted optical fiber may be arranged in parallel with other like fibers and axes twisted at different pitches thereby enabling detection of sound waves over a range of frequencies and their angles of incidence. (Author)

Descriptors :   *Patents, *Sonar transducers, *Direction finding, *Fiber optics transmission lines, *Acoustooptics, *Birefringence, *Acoustic detection, Optical detectors, Fiber optics, Angle of arrival, Sound pressure, Sound waves, Orthogonality, Phase shift, Dynamic range, Length, Optics, Frequency, Water, Parts, Fibers, Amplitude, Axes, Detection, Helium neon lasers, Polarization

Subject Categories : Acoustic Detection and Detectors
      Direction Finding
      Fiber Optics and Integrated Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE