Interferometric fiber-optic gyroscope performance owing to temperature-induced index fluctuations in the fiber: effect on bias modulation.

An analysis of the noise floor owing to temperature-induced index fluctuations in the fiber of a dynamically biased interferometric fiber-optic gyroscope is presented. A comparison with shot noise indicates that, for a harmonic bias modulation, thermal noise in the fiber dominates for fiber lengths longer than ~1-2 km when practical source power levels are considered. The noise can be reduced or eliminated by the proper choice of modulation frequency or waveform.