Accession Number : ADD015570

Title :   OMNI-Directional Hydrophone.

Descriptive Note : Patent, Filed 26 Nov 91, patented 13 Oct 92,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Fisher, Stanley A

Report Date : 13 Oct 1992

Pagination or Media Count : 7

Abstract : An omni-directional hydrophone having a pair of fiber-optic windings wrapped around a resilient ball to form a spherical acoustic sensor is provided. The fiber-optic pair has a first fiber which has a bonded jacket and a second fiber which has an unbonded jacket. The fiber with the bonded jacket is sensitive to both vibration of the mounting structure and impinging acoustic signals. The fiber with the unbonded jacket is sensitive to vibration but insulated from the acoustic signals. By comparing the signals from the two fibers, the hydrophone detects acoustic signals by detecting the phase difference between the two fibers. As both fibers are equally affected by vibration, there is no phase difference caused by vibration. This mechanization permits the canceling of vibration induced signals while retaining full sensitivity to acoustic signals. The hydrophone uses a standard fiber-optic laser source and detection system to convert the acoustic generated phase change to amplitude dependent voltage signals. The hydrophone is pressure and temperature insensitive.

Descriptors :   *FIBER OPTICS, *HYDROPHONES, *ACOUSTIC DETECTORS, *PATENTS, ACOUSTIC SIGNALS, ACOUSTICS, AMPLITUDE, DIRECTIONAL, FIBERS, JACKETS, LASERS, MECHANIZATION, PRESSURE, SENSITIVITY, SIGNALS, TEMPERATURE, VIBRATION, VOLTAGE, WINDING, SPHERES

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

Distribution Statement : APPROVED FOR PUBLIC RELEASE