The Research Of Key Features Of Special Optical Fiber For The Generation Of Supercontinuum Spectrum

The spectral width of supercontinuum spectrum (Supercontinuum, SC) is much larger than the width of the spectrum of incident light. It has important application prospects in the fields such as communication, sensing, medical imaging and so on. The design of high nonlinear optical fiber used to produce supercontinuum spectrum and the design of large effective area fiber used for amplification and transmission of high power pulse light source is the key technology of the system to generate supercontinuum spectrum. Because of the novel characteristics such as the high nonlinearity and large mode field area, the photonic crystal fiber is an ideal material to produce supercontinuum. By changing the corresponding parameters of photonic crystal fiber, we can obtain some novel optical properties that ordinary optical fiber does not have, such as endless single mode, high nonlinearity, single mode single polarization, large mode field area and so on.In this paper, we carried out the research of high nonlinearity and large mode field area of photonic crystal fiber. We have did a lot of simulation and calculation combining with the software of COMSOL Multiphsics and MATLAB. On this basis, we have designed different structure of optical fiber for different work wavelength, and analysis and study the fiber of special structure.The main work is as follows:1. We have analyzed the boundary conditions that should be considered in the process of COMSOL modeling.2. We have studied the PCF of different structures in this paper. A detailed comparative study to the fiber of different size of air hole cladding has been made. We have designed the high nonlinear fiber and the large mode field area fiber of different number of air holes. It can provide guidance for the design of optical fiber.3. The paper has designed different structures for high nonlinear photonic crystal fiber according to three kinds of wavelength that commonly used under the consideration of dispersion. Get the high nonlinear photonic crystal fiber of two zero dispersion wavelength. Finally, we have analyzed the photonic crystal fiber of large mode field area, and discussed some characteristics such as the mode field area, the dispersion and the nonlinear of the fiber.