Second order backscatter-induced crosstalk in a multiplexed two-dimensional gyro system

The single-axis Fibre Optic Gyroscope (FOG) has shown high sensitivity, wide dynamic range and long-term stability. However, most gyroscope applications involve the use of a cluster of instruments measuring rotations along orthogonal axes. For such systems clearly a network of individual gyroscopes may be used. However, there are advantages to energising all the gyroscopes in a cluster from a single source. However the use of a single source for several gyroscopes does introduce the possibility of crosstalk between the signals detected from each of the gyroscopes. For a frequency-division multiplexed fibre gyro system with a single and a single detector, crosstalk may be introduced by the effects of residual coherence or from first or second order backscatter. This paper concentrates on examining a particular source of backscatter (second order backscatter) induced crosstalk and assessing its influence on gyroscope performance.