Rotation Sensitivity of Gyroscopes Based on Distributed-Coupling Loop Resonators

This paper reports a theoretical study of a recently proposed coupled-resonator optical waveguide (CROW) gyroscope consisting of a Sagnac interferometer in which light is coupled between adjacent loops in the coil. Simulations show that after optimization, this gyroscope is less sensitive to rotation than a conventional resonant fiber-optic gyroscope (RFOG) made of a single loop. Instead, the sensitivity decreases as the number of loops is increased. The fundamental reason is that in both types of sensors, the sensitivity is proportional to the group delay, and the maximum achievable group delay is limited in the same manner by loss. In addition, this CROW gyroscope utilizes multiple resonators instead of one, so it is much harder to stabilize against external perturbations. The RFOG still stands as the ideal candidate for a compact resonant gyroscope.