Abstract: Methods and apparatus are provided for reducing output noise of optical gyros. The apparatus includes a sensing system for circulating counter-propagating light beams and producing an output light beam, a coupler having multiple ports and supplying an input light beam to the sensing system, a first detector coupled to the coupler for detecting a rotation rate based on the output light beam, a second detector coupled to the coupler for detecting noise based on the input light beam, and at least one optical device coupled to one of the ports of the coupler. The optical device is configured to reduce a spectral mismatch between the input light beam received by the second detector and the output light beam received by the first detector.

Abstract: Methods and apparatus are provided for calibrating a fiber optic gyroscope (FOG) to compensate for wavelength fluctuations. The wavelength of the light propagating in the gyroscope is accurately determined by obtaining wavelength indicia for light originally produced by the sensor light source and for light produced by a reference light source. The wavelength indicia may include normalized power values, such as sum and difference indicia, obtained from two outputs of a wavelength division multiplexer. Such information can be used to determine the wavelength of light produced by the sensor light source, and to adjust a scale factor or other operating parameter of the gyroscope as a function of the determined wavelength. This adjustment, in turn, can be used to compensate the output of the sensor to account for wavelength variations.

Abstract: Methods and apparatus are provided for reducing output noise of optical gyros. The apparatus includes a sensing system for circulating counter-propagating light beams and producing an output light beam, a coupler having multiple ports and supplying an input light beam to the sensing system, a first detector coupled to the coupler for detecting a rotation rate based on the output light beam, a second detector coupled to the coupler for detecting noise based on the input light beam, and at least one optical device coupled to one of the ports of the coupler. The optical device is configured to reduce a spectral mismatch between the input light beam received by the second detector and the output light beam received by the first detector.

Abstract: Fiber optic gyroscope architectures that incorporate both (i) a WDM-based wavelength control and (ii) a wavelength reference based on a narrowband fiber Bragg grating (FBG), with the latter component providing significant improvement in the stability of the wavelength reference by calibrating out wavelength errors associated with a WDM-based wavelength control scheme.