Dispersion-induced nonreciprocal effects in phase-nulling fibre gyroscopes

The nonreciprocal phase error introduced in phase-nulling gyroscopes by fibre dispersion is evaluated for a range of operating wavelengths and temperatures. It is found that small amounts of nonlinearity, scale factor change and zero bias arise, which all drift with temperature. However, if two frequency modulators are used to give zero-order fringe operation, dispersion-induced nonreciprocities have almost negligible effect on gyro performance.