Research About The Influence Of Spectrum And Polarization Characteristics On The Precision Of IFOG

As a novel inertial instrument, fiber optic gyroscope (FOG) has a lot of advantages, such as no moving parts, light weight, small volume and long lifetime. Which has already made it been widely applied to inertial navigation system. And it's always the research emphasis for researchers to improve the precise of FOG. Among all the infect factors, the transmission characteristic of light wave and optic component in the FOG's optical path influence much about the performance of FOG. This article focus on the transmission characteristic of FOG's optical path and studies the effects of spectrum and polarization properties on the precise of FOG The main researches of this paper are as follows:1. Analysis the reciprocity principle and coherent property of light wave in the FOG's optical path. The influence that spectral symmetry had on coherence property in FOG is studied by using the power spectrum density. Discussed the polarization relative theory. By using Poincare sphere method, analyzes the polarization coupling which caused by birefringence in optical path. It analyzes the relationship between parasitic effect and polarization state of FOG's optical path, and its influence on the optical path polarization.2. Based on the theory of matrix optical, the polarization transmission model of FOG's optical path and optical components are established. Then, we deduced the interference output model. According to the model and due to the change of the main performance parameters of FOG's optical components and the countershaft angles between fiber and components, their effect on the FOG output spectrum are simulated and analyzed.3. Analysis the computing method of light source's spectral performance index and its influence on the FOG's performance. Based on the coherence principle, simulate and analyzes the influence of light source's spectral characteristics on the FOG's precision,then checking it by the real experiment data. After that, we gained the light source's spectral characteristics that the FOG needs. By utilizing the FOG's optical path polarization model that established before,the article analyzes the influence of optical component's performance on the precision of FOG.4. Such a research is made aim at improving the transfer characteristic of IFOG's optical component. The parasitic error mechanism of IFOG that due to the spectral characteristics is analyzed and relevant restrain scheme is given. Proposed some methods to improve spectrum and polarization properties of light source. Then, further analyzed the transfer characteristic parameter of IFOG's Y waveguide, fiber ring and welding point. And some relevant craft and technical optimizing method which aim at improving the transfer characteristic of IFOG is proposed.