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Record Details

Record 44 of 100
Fiber Optic Microphone
Offline Availability: Go to Request Form
Author and Affiliation:
Cho, Y. C.(NASA Ames Research Center, Moffett Field, CA United States)
George, Thomas(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA United States)
Norvig, Peter [Technical Monitor]
Abstract: Research into advanced pressure sensors using fiber-optic technology is aimed at developing compact size microphones. Fiber optic sensors are inherently immune to electromagnetic noise, and are very sensitive, light weight, and highly flexible. In FY 98, NASA researchers successfully designed and assembled a prototype fiber-optic microphone. The sensing technique employed was fiber optic Fabry-Perot interferometry. The sensing head is composed of an optical fiber terminated in a miniature ferrule with a thin, silicon-microfabricated diaphragm mounted on it. The optical fiber is a single mode fiber with a core diameter of 8 micron, with the cleaved end positioned 50 micron from the diaphragm surface. The diaphragm is made up of a 0.2 micron thick silicon nitride membrane whose inner surface is metallized with layers of 30 nm titanium, 30 nm platinum, and 0.2 micron gold for efficient reflection. The active sensing area is approximately 1.5 mm in diameter. The measured differential pressure tolerance of this diaphragm is more than 1 bar, yielding a dynamic range of more than 100 dB.
Publication Date: Mar 09, 1999
Document ID:
20020080692
(Acquired Oct 25, 2002)
Subject Category: OPTICS
Document Type: Technical Report
Financial Sponsor: NASA Ames Research Center; Moffett Field, CA United States
Organization Source: NASA Ames Research Center; Moffett Field, CA United States
Description: 4p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: FIBER OPTICS; MICROPHONES; INTERFEROMETRY; ELECTROMAGNETIC NOISE; PERFORMANCE TESTS; PRESSURE SENSORS; EQUIPMENT SPECIFICATIONS
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