Analysis For The Characteristics Of Fiber Bragg Grating And Reconstruction Algorithm

Fiber gratings have many advantages,such as small bulk,low insert lost,low optical nonlinearity and so on, which make the fiber grating a most promising candidate device. As one of the most representative optical fiber passive components, has been widely used in optical fiber communication and fiber optic sensing. In the high-speed,ultra long-distance and high-capacity optical fiber communication systems, only effective dispersion compensation can meet the requirements of communications systems for further transmission, therefore, it has great significance for the solution of ultra long-distance transportion to research the FBG using for the dispersion management. Meeting to the dispersion of system, design fiber grating has important practical effect.In the first chapter of this thesis, the development process of the optical fiber, the appearance,development,photosensitivity,classification,production methods of optical fiber grating and the applications in optoelectronic devices,optical fiber communication,optical fiber lasers and fiber sensing are introduced in details, and then the importance of its application in dispersion compensation is shown, the background of this study is given.Coupling mode theory is expounded in detail, and the coupled-mode fiber grating equation is derived. The uniform fiber Bragg grating is analyzed on the basis of that, the analytical solution also is given. The transfer matrix method is introduced when analytical solutions can not be obtained by the traditional coupled equations for non-uniform fiber grating. This chapter is the theoretical basis of researhing on fiber grating. Finally, the basic principles of several FBG reconstruction methods are introduced, mainly including inverse scattering method and optimization algorithm.Using the coupled mode theory and the transfer matrix method, the reflection spectrum and delay characteristics of the uniform fiber Bragg gratings and chirped fiber Bragg grating are numerical simulated by mathmatica6.0, then the effect of the grating reflection spectrum and delay characteristics with various parameters are shown; the paper research on the inhibition of reflection spectrum sidelobe and delay wobble through apodized function ;finally the spectrum characteristics and delay of uniform sampling FBG and non-uniform sampling FBG are analyzed; and the effect of reflection spectrum and delay with various parameters is compared for the sampling FBG.The filter and dispersion compensator with different amount of dispersion are designed by the FBG synthesis method using Inverse Fourier transform method and the transfer matrix method.