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:
Jun. 12, 1990
Filed:
Jul. 21, 1989
Alan D Kersey, Springfield, VA (US);
Michael J Marrone, Severna Park, MD (US);
United States of America as represented by the Secretary of the Navy, Washington, DC (US);
Abstract
An apparatus for minimizing polarization-induced signal fading in an interferometric fiber-optic sensor is disclosed. The apparatus includes an optical source for providing an input light beam, a polarization modulator for modulating the state of polarization of the input light beam into at least three states represented by mutually perpendicular polarization vectors on a Poincare Sphere. The apparatus further includes means for conveying the input light beam with the at least three mutually perpendicular modulated states of polarization to the fiber-optic sensor, the interferometric fiber-optic sensor being responsive to the input light beam with modulated polarization states for developing an interference pattern output, wherein the interference pattern output has at least three visibilities corresponding to the input states of polarization. A photodetector is responsive to the interference pattern output for developing an electrical signal having at least three amplitudes corresponding to the at least three states of polarization. An output circuit is responsive to the electrical photodetector signal for time-sampling the photodetector signal having three amplitudes corresponding to the at least three mutually perpendicular input states of polarization and selecting the one having maximum visibility. A method for minimizing polarization-induced signal fading is also disclosed.