Zero-crossing demodulation for open-loop Sagnac interferometers

This paper describes a new low-cost signal processing scheme for open-loop Sagnac interferometers. An extended computer simulation has been performed in order to determine the optimum parameters of the system providing dynamic range, bias drift, scale factor stability and random noise performances suitable for AHRS grade fiber gyroscope applications and metering grade current sensor applications. The signal processing scheme has been assembled and tested in the laboratory using a commercial gyroscope produced by Honeywell, Inc. Several alternative demodulation circuit implementations have been proposed, built and experimentally investigated.