Design And Simulation Of Photonic Crystal Functional Devices

Photonic crystals (PCs) are periodic dielectric structures fabricated artificially, which exist photonic band gap and the propagation of electromagnetic waves with frequencies within the gap are forbidden. As the basic materials of the integrate photics, PCs exhibit promising future in optical integrated circuits (OIC) and all optical communication systems. People have been wild about exploring the new-style function devices of the PCs. In this thesis, we focus on the theoretical research of photonic crystal applications with the cut-in point of fundamental design of photonic crystal function devices.The method of Finite Difference Time Domain (FDTD) and directional coupling theory of the medium waveguides are used as the basic theory. A field comes out through the input waveguide when the coupler length is an integer multiple of the beat-length. In contrast, the field injected into one waveguide switches entirely to the other one if the coupler length is an odd multiple of half the beat-length. A three-wavelength photonic crystal multiplexer is designed. And a method to compute the group velocity by the coupling length is presented also, which will be useful in the research of the dispersion of the PC fibers.In this thesis, we make theoretical research on the structures of the band gap of one dimensional (1-D) PCs containing negative refraction material by means of numerical simulation: the PCs containing negative refraction materials have wider photonic band gaps (PBG) than the traditional PCs, and have narrow transmission bands with the edge of the PBG changeing monotonic and without ripples. The photonic thickness and the period to the infection of the band gap have been discussed, the results says that the transmission bands have the periodic characteristic with equal photonic thickness, and the PBG become wider when of the period increases.Based on the characteristics of the negative refractive materials and the nonlinearity, we design a 1-D PC switching with negative and nonlinear materials which satisfy the condition of the equal thickness, whose response time reaches 10^-14. Also, we design a 2-D PC switching with nonlinear materials, discussing the different transmission situations by controlling the intensity of the input light. It's shown that the switching time is wondrous short, approaching 10^-13-10^-14.