(12) United States Patent ao) Patent No.: Us 7,697,121 Bi
Coroy et al. (45) Date of Patent: Apr. 13,2010
(54) SENSING SYSTEM HAVING WAVELENGTH REFLECTORS THAT RECEIVE MODULATED LIGHT SIGNALS
(75) Inventors: Trenton Gary Coroy, Niverville (CA);
Bernard Thomas Smith, Sierra Madre
(73) Assignee: Kotura, Inc., Monterey Park, CA (US)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 481 days.
(21) Appl.No.: 11/292,317
(22) Filed: Nov. 30, 2005
(51) Int. CI.
G01B 9/02 (2006.01)
(52) U.S. CI 356/35.5; 356/478
(58) Field of Classification Search 356/32,
356/35.5,478; 250/227.23,227.27; 385/12 See application file for complete search history.
(56) References Cited
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T. Coroy. Bragg fiber optic sensing systems for structural sensing. In OSA Trends in Optics and Photonics vol. 23, Symposium on Electro
The sensing system includes a plurality of modulators that are each configured to modulate a different light signal. The sensing system also includes optical pathways that transport the modulated light signals to one or more wavelength reflectors. Each wavelength reflector is configured to reflect a portion of the modulated light signals at a characteristic wavelength that is a function of an influence external to the wavelength reflector. The sensing system also includes a light sensor configured to receive the reflected light signals and to output a modulated electrical signal that is a function of the power of each of the reflected light signals. The sensing system can also include electronics configured to employ the modulated electrical signal so as to determine one or more results selected from a group consisting of: the characteristic wavelength of one or more of the wavelength reflectors and a level of the external influence on one or more of the wavelength reflectors. Examples of external influences include, but are not limited to, strain, stress, temperature, and properties of materials contacting the wavelength reflector such as index of refraction or pH.
22 Claims, 4 Drawing Sheets