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:
Apr. 30, 1991
Filed:
Mar. 31, 1989
James H Cole, Great Falls, VA (US);
Ira J Bush, Los Angeles, CA (US);
Other;
Abstract
An optical sensor and method for measuring naturally occurring phenomena such as vibrations is disclosed. An optic fiber is wound as a coil and placed such that strain is introduced in it by the phenomena. Low coherence light is launched through a coupler and split to produce counter rotating beams in the coil. The counter rotating beams are phase modulated by an optical modulator driven by an oscillator and by naturally occurring phenomena. The sensitivity and response of the sensor increases dependent on the length of fiber in the coil and improves linearly as the frequency of source signal increases. The modulated counter rotating beams are recombined in the coupler to produce an intensity modulated optical signal on a photodetector. The output of the detector is an electrical signal containing the signal of interest as modulation which is recovered througth demodulating circuits mixing the fundamental and second harmonic frequencies.