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: A system and method is provided for reducing the sensitivity of the rotation rate measurement to the frequency dependence of the feedback modulator. Specifically, the system and method uses a minimal bias switching technique to reduce rate errors associated with the low frequency 2? resets in a closed loop fiber optic gyroscope with a phase modulator with a different phase shift associated to low and high frequencies. In general, the minimal bias switching technique reduces the low frequency components of the feedback modulation drive by increasing the frequency of the 2? resets. As a consequence, the system and method reduces the low frequency component of the feedback modulator drive to avoid errors that occur with the low frequency 2? resets.

Abstract: A clock system for a fiber optic gyroscope is provided that includes a highly-tunable clock for the bias modulation and a separate asynchronous high-speed clock for the photodetector sampling. By separating the two clocks rather than using two derivatives of the same clock, the clock system and method can provide both the tunability objective of the bias modulation clock and the high-speed objective of the sampling clock, while using readily available, lower performance, radiation-hardened electronics parts.

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.