Analysis of Noise in Phase Detection in a Fiber Optic Rate Sensor

Abstract

The mathematical analysis of the effect of noise on the detection of optical phase shift in a fiber optic rate sensor must be based upon appropriate mathematical modeling of the noise. Noise may be categorized as being (I) additive to the optical field, (2) additive to the phase of the optical field, (3) multiplicative to the detector signal current, or (4) additive to the signal current. Because the rate information is contained within the phase of the detector current, it is the level crossings of the detector current that contain the desired information. We consider the effects of two types of noise on the level crossings of the signal current — that due to the optical source which is additive to the optical field, and that due to the polarization fluctuations of the two counter-propagating optical fields in the fiber gyro which is multiplicative to the signal current.