The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 29, 1995
Filed:
Aug. 31, 1993
Anbo Wang, Blacksburg, VA (US);
Kent A Murphy, Roanoke, VA (US);
Richard O Claus, Christiansburg, VA (US);
Center for Innovative Technology, Herndon, VA (US);
Virginia Polytechnic Institute and State University, Blacksburg, VA (US);
Virginia Tech Intellectual Properties, Inc., Blacksburg, VA (US);
Abstract
A fiber optic sensor is fully compensated for light source intensity variation, fiber losses and modal power distribution by providing input to one end of an optical fiber from a relatively broad band light source containing at least two spectrally separated wavelengths. At least one of these spectrally separated wavelengths is reflected back into the optical fiber by a filter located between a second end of the optical fiber and a reflective transducer. The filter is preferably of the interference edge filter type and has a nominal cut-off wavelength within the spectral band of the light source or between the two spectrally separated wavelengths. Therefore, the paths traversed by light of the spectrally separated wavelengths will differ only by twice traversing the reflective transducer. Temperature measurement or compensation can also be provided by sensing of reflected light intensity or power at approximately the nominal cut-off frequency of the filter. Reflective transducers of both the intensity-based and interferometric types are usable with the invention.