High dynamic range fiber optic gyroscope demodulation technique based on triangular waveform phase modulation

This work describes, in an elucidative fashion, a high dynamic range demodulation technique suitable for open-loop Fiber Optic Gyroscope (FOG) application. The proposed technique relies on special features which are achieved when an integrated optic phase modulator is driven by a triangular waveform signal. Such modulation, combined with the zero crossing technique yields detection of Sagnac phase shift with a dynamic range 30 dB above the sinusoidal driven approach. The dynamic range obtained has an upper boundary that is limited by the optical source coherence function. The experimental results obtained using a Sagnac interferometer are in agreement with the theoretical predictions