A major source of noise in fiber-optic Sagnac interferometers was identified to be the fluctuation of the phase of Rayleigh backscattering resulting from minute temperature variations and vibration. This noise can be reduced either by introducing a phase modulation into the fiber ring or by the use of a low-coherence source. A noise-equivalent rotation rate of 8 × 10-4 deg/sec was achieved.
© 1981 Optical Society of America
K. Böhm, P. Russer, E. Weidel, and R. Ulrich, "Low-noise fiber-optic rotation sensing," Opt. Lett. 6, 64-66 (1981)