Research On Mid-IR Supercontinuum Generation In Nonsilica Microstructed Optical Fibers

Compared with the conventional fibers, photonic crystal fibers have some uniquecharacteristics, which make photonic crystal fibers exhibit wider applicationpotentials in the field of optical communication. In recent years, with the drawntechnology of optical fiber, it is possible to drawn nonsilica microstructed fibers,which can be used to the field of mid-IR supercontinnum generation. In this thesis,the mid-IR supercontinuum generation in nonsilica microstructed fibers is studied.The main results are listed below:Firstly, effects of the dispersion, nonlinearty and incident central frequecy, width,energe to Mid-IR supercontinuum generation have been studied. We designed fiberswith different dispersion curves by using the multipole method. Features of a lot ofnosilicate glasses had been considered, such as linearty, nonlinearty and multiphononabsorption edge. Then, we researched the spectral broadening according to thenonlinear Schrodinger equation. The research results indicate that, for the nonsilicamicrostructured fiber with two appropriate lying zero dispersion wavelengths, mostwidely mid-IR supercontinuum can be generated by pump pulses in the nearly mid ofthe two zero dispersion wavelengths.Secondly, a newly microstructured fiber which we believe to be first demonstratedhad been designed. The fiber has high nonlinear coefficient, widely flattenedchromatic dispersion, lower confinement loss, and a single mode operation in themid-infrared range. Numerical simulations are used to research the mid-infraredsupercontinuum generation. We find that a widely mid-IR supercontinuum can begenerated covering from1.5μm to5.5μm. The reason is mainly attributed to theamplification of the dispersive waves in the initial propagation.