DEEP PHASE-MODULATION APPROACH TO AN OPEN-LOOP FIBER OPTIC GYROSCOPE

A new approach to an open-loop, all-fiber gyroscope with wide dynamic range and linear scale factor is described. For signal processing, the Sagnac phase lift is converted into a phase shift in the low-frequency electrical signal by using a deep sinusoidal phase-modulation waveform followed by gate-switching. With the duty cycle of the gating signal selected to be in the range between 20 and 70%, the scale factor is stable with respect to change in the amplitude of the phase modulation signal by as much as 15%. The basic principle of this technique and experimental results are reported.