Open loop fibre optic gyroscope with phase shift nulling signal processing

A simple analogue phase tracking circuit for the fibre gyroscope is described. The system provides a linear output from an open loop gyroscope configuration over a range in Sagnac phase shift >+or-500 degrees Sagnac, with good linearity and relatively low noise and drift. The use of this demodulator in low-cost medium grade fibre gyroscope applications is projected.