Resonator fiber optic gyroscope with an all digitalized system

Resonator fiber optic gyroscope has the potential to achieve the inertial navigation system requirement with a short sensing coil. An all digitalized system is constructed including the signal modulation/demodulation and a proportional integral (PI) controller in a single field programmable gate array. Under this scheme, the serrodyne phase modulation technique is adopted, which is of benefit to overcome the backscattering induced noise and easy to implement in closed-loop operation. The phase modulation index is optimized to achieve high carrier suppression. The PI controller is adopted in the frequency servo loop to eliminate the residual error at the lock-in frequency. A bias stability of 5.2×10^-4 rad/s in 500 seconds is demonstrated experimentally.