Research On The Influence Of Erbium-doped Fiber Source On Fiber Optic Gyroscope

With the extensive application of fiber optic gyroscope (FOG) to inertial navigation system, the improvement of its accuracy becomes the focus of current research. The source's performance directly affects the gyroscope's performance as a significant sensor carrier emission source of FOG. In order to design a erbium-doped fiber source (EDFS) used in high-precision FOG, this paper has done the following researches and laid the foundation for the performance improvement of the future erbium-doped fiber source and fiber optic gyroscope.This paper starts from the light path of EDFS, discusses the physical parameters and the luminescence mechanism of the source in detail, establishes a physical model of the double-pass backward (DPB) structure of EDFS, analyzes the influence of EDFS's four key parameters: spectral width, output power, mean wavelength stability, polarization properties on FOG and high-precision gyroscope's demands of the four parameters, puts forward some solutions in order to meet these demands.From optical coherence of fiber source, transmission conditions in single-mode fiber and the producing mechanism of rayleigh backscattering noise, polarization non-reciprocity errors in the fiber optic gyroscope, the high-precision gyroscope's demands of spectral width and spectral width fluctuations are analyzed.From the gyroscope's signal detection and the detector's output signal to noise ratio, the influence of fiber source's output power and power fluctuations on FOG's detection sensitivity and measurement accuracy is analyzed, and high-precision gyroscope's demands of the source power and power stability are put forward.The influence of mean wavelength stability on gyroscope's measurement accuracy is analyzed, and the influence of five parameters on the mean wavelength of EDFS is described in detail such as temperature, pump power, pump wavelength, return power, pump polarization. Several methods are proposed and the index parameter of the mean wavelength stability is raised.The transfer matrix of the polarized light transferring through Y waveguide is established on the basis of entire fiber optical path and the gyroscope's requirement of source's polarization state is analyzed. And some measures towards to source's polarization are proposed.In the end of this paper, the entire fiber source system has been tested, the best spectral width values are simulated under the environment of wide spectrum of fluctuations, and a erbium-doped long period fiber grating filter towards to the laboratory's output original spectrum is designed.