Study On High Stability And Flattening Of Erbium-Doped Fiber Source

Studied the high stability and flattening erbium-doped fiber source. As the crucial component of the fiber optic gyroscope, fiber source plays a decisive role in gyroscope's accuracy and stability performance. High stability, wide spectrum, high-flatness and high-power erbium-doped fiber source is the ideal source with the most development potential of high-precision fiber optic gyroscope. Therefore, studying on high-precision source for fiber optic gyroscope has important practical value. Researched erbium-doped fiber source theoretically and experimentally, mainly summarized as follows:Firstly, we researched erbium-doped fiber source theoretically. The development background at home and abroad of erbium-doped fiber source was summarized. The basic structure of four kinds of sources and the principle was described. Through the structure simplified model based on the energy levels of erbium ions, using the three-level system model of laser and the transmission of source equation, established erbium-doped fiber source's corresponding mathematical model of the structure with boundary conditions. Explained the theoretical basis of output parameters and temperature stability characteristics of erbium-doped fiber source.Secondly, researched double pass forward and backward erbium-doped fiber source experimentally. Selected reasonable variety of experimental components, and set up a source. Experimentally tested erbium-doped fiber temperature coefficient of the intrinsic and analyze the impacts of erbium-fiber length and pump power on the source. Thus determined the erbium fiber length and pump power, and obtained the double pass forward and backward source on the fiber length of 12.2 m and 10.1 m respectively, with pump power 150 mW and 160 mW respectively. Assembled two fiber source prototypes, and tests temperature stability, then obtained mean wavelength stability of the double pass forward and backward source -0.557 ppm/℃and -1.18 ppm/℃respectively.Finally, studied the gain flattening methods of the erbium-doped fiber source. Summarized gain flattening filters with the classification, characteristics, principle and the advantages and disadvantages. Using dielectric thin-film filter, experiments have been done on double pass forward and backward sources. Gained spectral flatness within±1 dB and±1.2 dB respectively, 3 dB spectral width of 24.8 nm and 23.3 nm respectively. Using cascaded long-period fiber grating filters, gained spectral flatness within±1.5 dB and±1.2 dB respectively,3 dB spectral width of 26 nm and 29 nm respectively. In the end, test the transmission spectra of two kinds of filters, get filters' temperature influence on erbium-doped fiber source, about -0.155 ppm/℃and 4.78 ppm/℃respectively.