Simulation Of Optical Properties And Optimal Designing Of Photonic Crystal Fibers

Photonic crystal fibers have been attracting increasing interest all over the world in the recent decade. The research areas include numerical simulation and charictizing of their basic optical properties, structure design, preparation and potential applications of the photonic crystal fibers. With the development and improvement of the fabrication technology, many kinds of photonic crystal fibers have been manufactured successfully, and the transmission loss has reached a level as low as conventional fibers. Photonic crystal fibers possess many excellent optical properties, and their opportunities in optical communication, fiber sensor and other fiber related applications are promising. In this thesis, through optimizing the structure parameters, some photonic crystal fibers have been designed. The main contents are described as follows:(1)Using multipole method, dispersion properties and mode area of photonic crystal fibers are analyzed. An octagon lattice photonic crystal fiber is designed. The structure parameters'influences on the effective index, dispersion, mode area and confinement loss are considered. A kind of photonic crystal fiber with elliptical holes in the claddings is designed. Using the finite element method, its parameter influences on dispersion, mode area, loss and birefringence are analyzed.(2)The nonlinear properties of photonic crystal fiber are investigated, the way to enhance the nonlinear coefficient are introduced. The relation between structure parameter and nonlinear coefficient, the relation between wavelength and nonlinear coefficient of photonic crystal fibers are analyzed. The dispersion properties and nonlinear coefficient of the highly nonlinear photonic crystal fiber with dispersion flattened and low dispersion near 800 nm are analyzed.(3)The conditions of using photonic crystal fiber for dispersion compensation are investigated. Using the multipole method, the dispersion, the dispersion slope and the relatively dispersion slope as a function of fiber parameters are simulated near the wavelength of 1 550 nm. The influences of the hole-diameter and distribution formation of first three layers on the dispersion, dispersion slope and the relatively dispersion slope are analyzed. A double-cladding photonic crystal fiber with different lattices in the two claddings is designed, and its dispersion as a function of structure parameters is analyzed.(4)Using the plane-wave expansion method, the photonic bandgap and modal properties of the photonic bandgap-type fiber with a triangular lattice cladding is researched. The influence of the interstitial holes on the photonic bandgap is analyzed.(5)Using the improved stacking capillary method and the eroded die method, some photonic crystal fibers are fabricated. The nonlinearities of some photonic crystal fibers are experimentally investigated by using femtosecond pulse laser, and their transmission spectra are also measured. The experimental results are compared with the simulation results using the plane-wave expansion method and found to be consistent with each other.