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:
Jan. 05, 1999
Filed:
Jul. 28, 1997
John P Rahn, West Hills, CA (US);
Ralph A Patterson, MoorPark, CA (US);
Litton Systems, Inc., Woodland Hills, CA (US);
Abstract
The invention is a method and apparatus for quantitatively characterizing the pressure-induced nonreciprocity of a fiber-optic coil where the pressure-induced nonreciprocity is a property of a fiber-optic coil which pertains to the degree to which light beams, initially in phase, differ in phase as a result of traversing the fiber-optic coil in reverse directions while the fiber-optic coil is being subjected to a time-varying pressure. The method comprises the steps of applying time-varying pressure to the fiber-optic coil for a predetermined time period, measuring the phase difference of light beams traversing the fiber-optic coil in reverse directions during the predetermined time period, and obtaining a measure of the nonreciprocity of the fiber-optic coil utilizing the measured phase difference. If the time-varying pressure is specified by a first function of time, the measure of the nonreciprocity is the integral over the predetermined time period of the product of a second function of time and either (1) the phase difference of light beams traversing the fiber-optic coil in reverse directions during the predetermined time period or (2) the integral over time of the phase difference. The second function is chosen such that the measure of the nonrecipocity has a signal-to-noise ratio of at least one. Preferably, the second function is (1) an approximation of the time derivative of the first function if the product involves the phase difference or (2) an approximation of the first function if the product involves the integral of the phase difference. The invention also includes the apparatus for practicing the method.