Fabry-perot optical sensing device for measuring a physical parameter

Patent 5202939 Issued on April 13, 1993. Estimated Expiration Date:

July 21, 2012. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

Fiber optic interferometric thermometer with serially positioned fiber optic sensors
Patent #: 4755668
Issued on: 07/05/1988
Inventor: Davis

Optical communication systems using Fabry-Perot cavities
Patent #: 4861136
Issued on: 08/29/1989
Inventor: Stone , et al.

Progressively monitorable fire alarm system Patent #: 4994791
Issued on: 02/19/1991
Inventor: Taylor

Inventors

Assignee

Application

No. 915645 filed on 07/21/1992

US Classes:

385/12, OPTICAL WAVEGUIDE SENSOR250/227.27, With coherent interferrometric light356/480, Resonant cavity356/519, Having partially reflecting plates in series (e.g., Fabry-Perot type)385/18Reflective-type switch

Examiners

Primary: Lee, John D.
Assistant: Heartney, Phan T.

Attorney, Agent or Firm

Foley & Lardner

Foreign Patent References

0143645 EP. 06/13/1985

International Class

G02B 006/26

Abstract

The optical sensing device and the method thereof are for measuring a physical parameter. The device is to be connected to a light source which generates a multiple frequency light signal having predetermined spectral characteristics. The device comprises a Fabry-Perot interferometer through which the light signal is passed, an optical focusing device for focusing at least a portion of the light signal outgoing from the Fabry-Perot interferometer, and a Fizeau interferometer through which the focused light signal is passed. The Fabry-Perot interferometer includes two semi-reflecting mirrors substantially parallel to one another and spaced by a given distance so as to define a Fabry-Perot cavity having transmittance or reflectance properties which are affected by the physical parameter and which cause the spectral properties of the light signal to vary in response to the physical parameter. The Fabry-Perot interferometer is provided with at least one multimode optical fiber for transmitting the light signal into the Fabry-Perot cavity and for collecting the portion of the light signal outgoing thereof. The Fizeau interferometer includes an optical wedge forming a wedge-profiled Fizeau cavity from which exits a spatially-spread light signal indicative of the transmittance or reflectance properties of the Fabry-Perot interferometer. The physical parameter can be determined by means of the spatially-spread light signal.

Other References

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