Scale-Factor Stability Control Technique for Closed-Loop All-Fiber Interferometric Optical Gyroscope

The paper presents an effective method for scale-factor stabilization and modulation depth control in a low-cost all-fiber interferometric gyroscope utilizing a piezoelectric phase modulator to perform modulation for biasing as well as compensation of the Sagnac phase shift in a closed-loop. The technique uses a virtual-sensor approach consisting in deriving the actual compensation shift from comparison of the real and the modeled gyroscope output intensity signals. The first experimental results are provided, suggesting that the model-base approach can decrease the scale-factor drift by more than one order of magnitude to reduce significantly the effect of the modulator parameter instability.