Optics: measuring and testing – By particle light scattering – With photocell detection
Patent
1997-03-19
1999-07-27
Turner, Samuel A.
Optics: measuring and testing
By particle light scattering
With photocell detection
356352, G01B 902
Patent
active
059299908
ABSTRACT:
A pressure sensing system employs a plurality of pulsed, single-wavelength optical signal sources, each emitting a distinct wavelength, whereby a multiplexed incident beam is generated. The incident beam is split into a first portion directed to first photodetector means that generate a reference signal for each wavelength, and a second portion that interrogates one or more Fabry-Perot pressure sensors. The interrogation beam portion is phase-modulated by gap width variations in the sensor(s), and is transmitted to second photodetector means that generate a measured intensity signal for each wavelength. For each wavelength, the ratio of the measured intensity signal to the reference intensity signal is taken, and yields two terms, one of which is an interference term that is proportional to the cosine of the Fabry-Perot phase shift angle .phi., which is a function of the gap width. By choosing wavelengths that are in quadrature relationship for a nominal Fabry-Perot gap width, the algebraic differences can be taken among the ratios to yield two expressions proportional, respectively, to the cosine and sine of the phase shift angle .phi.. An arctangent calculation is used to obtain the measure of .phi., which is proportional to the gap width, which, in turn, is a known function of the pressure applied to the sensor. The optical sources may be pulsed sequentially to provide a time division-multiplexed incident beam, or simultaneously to provide a wavelength division-multiplexed incident beam.
REFERENCES:
patent: 4283144 (1981-08-01), McLandrich
patent: 4873989 (1989-10-01), Einzig
patent: 4897542 (1990-01-01), Dakin et al.
patent: 5200795 (1993-04-01), Kim et al.
patent: 5367583 (1994-11-01), Sirkis
Halg, B. "A Silicon Pressure Sensor with an Interferometric Optical Readout", 1991 International Conference on Solid State Sensors and Actuators, IEEE Catalogue No. 91CH2817-5, pp. 682-684 (1991).
Bush, Jeff, et al. "Low Cost Optic Interferometric Microphones and Hydrophones", SPIE vol. 2292. Fiber Optic and Laser Sensors XII, pp. 83-93 (1994).
Lourenco et al, "Data Processing for Intensity Based Fiber Optic Sensors", Engineering & Laboratory Notes, (1996).
Litton Systems Inc.
Turner Samuel A.
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