Bias of interferential fiber optic gyro induced by parasitical intensity modulation of light source

The best way to suppress the drift is to suppress the bias. To all digital close loop interferential fiber optic gyros (IFOG), the disturbance on constant-current driving of light source induced by modulation-demodulation reference signal was analyzed. Based on close-loop detection fundamental, the proportion between the disturbance and its equivalent phase delay was deduced and equivalent bias according to different performance IFOG was presented. The disturbance was tested by lock-in amplifier (LIA) which verified the correlation of the disturbance and the reference signal. The correlation was depressed sufficiently by modified the design of light source drive. The experimental results show that the coherent intensity modulation of light source is one of the factors of IFOG bias.