The Research On PM-IFOG's Optical System Bias Stability

Fiber optic gyroscope(FOG) is a novel rotary device. Compared with mechanical gyroscope, it is small in volume, light in weight, shock-resistant and all solid state structure. They have attracted public attention widely since its appearance. The study on FOG develops rapidly in universities, national laboratories and companies. With the deepening of the study, the moderate highly accurate FOG have already been developed successfully, but the problem of its stability has always been an important factor which influences the accuracy of the FOG. The purpose of this paper is to analyze the optical characteristic of a PM-IFOG system, find out the cause of drift and discuss the compensation methods for it. The main research work concentrates on the aspects as follows:In this paper firstly gives a view of the FOG's future, and analyzes the principle of the PM-IFOG and the principle of ladder wave modulation. And the important optical components of the FOG are studied, in the research about the performance parameters, noises of optical components and the causes they produced, we find some methods to filtrate the components.Secondly the mathematical model of the optical transmission system with coherence matrix is established. Based on the model mentioned above, a theoretic analysis on the optical path polarization is made, an expression of the polarization error is acquired, and the influences of each apparatus on polarization noise are discussed. The conclusion of this paper can be used for the continued research.Finally newly introduced an optical fiber isolator into the optical system, the principle of the optical isolator is studied with the Jones matrices. The insertion loss, return loss and isolation of a dual stage optical isolator are measured experimentally. And the influence of Fresnel reflection is studied and simulated.