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Title: Fiber optic hydrophone

A miniature fiber optic hydrophone based on the principles of a Fabry-Perot interferometer. The hydrophone, in one embodiment, includes a body having a shaped flexible bladder at one end which defines a volume containing air or suitable gas, and including a membrane disposed adjacent a vent. An optic fiber extends into the body with one end terminating in spaced relation to the membrane. Acoustic waves in the water that impinge on the bladder cause the pressure of the volume therein to vary causing the membrane to deflect and modulate the reflectivity of the Fabry-Perot cavity formed by the membrane surface and the cleaved end of the optical fiber disposed adjacent to the membrane. When the light is transmitted down the optical fiber, the reflected signal is amplitude modulated by the incident acoustic wave. Another embodiment utilizes a fluid filled volume within which the fiber optic extends.
Inventors:
 [1];  [1]
  1. (Livermore, CA)
Issue Date:
OSTI Identifier:
869294
Assignee:
United States of America as represented by United States (Washington, DC) LLNL
Patent Number(s):
US 5311485
Contract Number:
W-7405-ENG-48
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Country of Publication:
United States
Language:
English
Subject:
fiber; optic; hydrophone; miniature; based; principles; fabry-perot; interferometer; embodiment; shaped; flexible; bladder; defines; volume; containing; air; suitable; gas; including; membrane; disposed; adjacent; extends; terminating; spaced; relation; acoustic; waves; water; impinge; pressure; therein; vary; causing; deflect; modulate; reflectivity; cavity; formed; surface; cleaved; optical; light; transmitted; reflected; signal; amplitude; modulated; incident; wave; utilizes; fluid; filled; volume containing; amplitude modulated; membrane surface; fluid filled; embodiment utilizes; fabry-perot interferometer; spaced relation; optic fiber; acoustic wave; disposed adjacent; fiber optic; optical fiber; acoustic waves; cavity formed; suitable gas; reflected signal; fabry-perot cavity; containing air; shaped flexible; optic hydrophone; /367/