Direct measurement of Sagnac phase shift from an open-loop, all-fiber-optic gyroscope using signal processing is described. The photodetector output from a phase modulated gyro is amplitude modulated at the phase modulation frequency to transpose the optical phase shift into a low frequency electronic phase shift, which is measured using a digital time interval counter. A wide dynamic range and linear scale factor are demonstrated using this approach.
B. Y. Kim,
H. J. Shaw,
"All-Fiber-Optic Gyroscope With Linear Scale Factor Using Phase Detection", Proc. SPIE 0478, Fiber Optic and Laser Sensors II, (17 September 1984); doi: 10.1117/12.942681; https://doi.org/10.1117/12.942681