Research On Flattened Dispersion And High Nonlinear Of Photonic Crystal Fiber

In recent years,photonics crystal fiber widely used in the field of optical fibercommunication as a mature communication medium. It has become hot researchtropic in designing, manufacturing and applicating of photonic crystal fiber. Thedispersion, nonlinearity properties of octagonal photonic crystal fibers(O-PCF) areinvestigated theoretically in this paper. Three kinds of octagonal photonic crystalfibers have been designed, The main results are summarized as follows:Firstly, A novel octagonal photonic crystal fiber with step-structure wasnumerically calculated by using FDTD, This kind of O-PCF has broadbandultra-flattened lower dispersion.At the range of wavelength1.1—1.9m,thedispersion coefficient merely changing from-0.5—1.5ps/(km nm). The influences onthe dispersion from the air hole diameters and hole pitch was also analysed.Secondly, In order to obtain a new flattened dispersion photonics crystal fiberwith high nonlinearity, A novel octagonal photonic crystal fiber(O-PCF) structure isproposed. The effect of hole size on nonlinearity and dispersion of the PCF isanalyzed by the multi-pole method. By optimizing the diameters of the O-PCF holesand the hole pitch, a O-PCF with high flattened dispersion and nonlinearity isachieved. At the range of wavelength1.46—1.73m,the dispersion coefficient ismerely changed within±0.5ps/(km nm), and the nonlinearity coefficient is merelychanged from42.5to50(1/w-km) between1.5to1.65micron。Finally, A new O-PCF with two zero-dispersion is designed,The effect of holesize on nonlinearity and dispersion of the two zero-dispersion O-PCF is analyzed bythe multi-pole method. by optimizing the geometrical parameter, the twozero-dispersion O-PCF with high nonlinearity and nearly zero ultra-flatteneddispersion was obtained in theory.At the range of wavelength1.47—1.6μm,thedispersion coefficient is merely changed within±0.5ps/(km nm), and the nonlinearity coefficient is40.5(1/w-km) at1.55m.