Patent ID: 7505139
Filing Date: 2009-03-17
Classification: G01C

Abstract:
1. A method of modulating the phase difference between a pair of optical waves that exit a Sagnac interferometer after having counter-propagated through a common optical path, including an optical fiber and a phase modulator, and impinges upon a detector that produces a detector output signal responsive to the combined optical power of said pair of optical waves and is indicative of the total phase difference between the pair of optical waves, and wherein the total phase difference includes (i) the Sagnac phase difference, and (ii) a phase-difference modulation induced by said phase modulator in response to a command signal, and wherein said phase modulator is capable of imparting phase modulation substantially equally to said counter-propagating waves passing therethrough, the method comprising the steps of: driving said phase modulator with a command signal [S] that causes said phase-difference modulation between said pair of optical waves to have deriving a rotation-rate feedback phase-difference component signal [R] as a function of, deriving a calibration signal [G] corresponding to a selected phase difference as a function of, deriving said calibration feedback phase-difference modulation component signal [Y] by modulating said calibration signal [G] in part to restrict the command signal [S] to a given range of values, and deriving said command signal [S] as a function of,