On Noise Analysis and Modulation Mode of Time-Division Multiplexing Fiber Optic Gyroscope

It is difficult for modulation mode selection and noise analysis in time-division multiplexing multi-axis Fiber Optic Gyroscope(FOG),thus we analyzed the optical and electrical crosstalk factors in condition of square wave modulation and step wave feedback.It was provided that noise on photoelectric detector was the most important factor affecting time-division multiplexing FOG in medium or low precision applications.Relation of signal and noise on photoelectric detector was analyzed for three modes of square wave modulation: all axes modulated at ±π/2;one axis at ±π/2,others null and one axis at ±π/2,others at ±π.The SNR of working axis and the minimum detectable phase shift were also computed as the shot noise was predominant.Simulations and experiments showed that later two modulation modes are more practical than the former one.Modulation of one axis at ±π/2,others at ±π has the highest SNR and its sensitivity is5 times of the former mode,which provides a reference for FOG application.