The Research On Photonic Crystal Defect And Waveguide

The information industry in the 20th century is based on the electrommunication, but the electron as one kind of information carrier, can't meet with the high-speed communication. People find one faster carrier, the photon, to replace the electron. The material that can control the photon is photonic crystal. There are broad applications with the perfect photonic crystal, but the photonic crystal with defect is more popular for researchers. We can use the defect in the photonic crystal to guide the electromagnetic wave, and this photonic crystal with defect can be used to make photonic crystal devices. The purpose of this paper is to study the dot defect and line defect in photonic crystal, waveguide and demultiplexer.The band structures of square lattice photonic crystal and hexagonal lattice photonic crystal have been computed in the second chapter. The results indicate that there is a smooth and isolated band in the band gap if photonic crystal has a dot defect. Appearance of this isolated band means that there will be a very high transmission rates for electromagnetic wave with certain frequency. This character of the photonic crystal containing defect can be used to enhance spontaneous emission of atoms and to make narrow band filter. In order to carry out the numerical computation of the photonic crystal, people have been doing their best to seek the new computing technology. In the 3 rd chapter, we have analyzed the reflection coefficient, character equation and field distribution of one dimensional photonic crystal waveguide with a new numerical method—the impedance analytical method. The calculated results of transmission coefficient indicate that this new method can be applied to compute photonic crystal and total internal reflection. We also get the relation between normalized propagation constant and wavelength of the first forth modes by solving the character equation of one dimensional photonic crystal waveguide with the impedance method. The results are identical with the relevant papers.In general, people are more interested in the photonic crystal with defect, because the defect in photonic crystal can localize and guide electromagnetic wave. We have calculated the band structure and localized modes of two dimensional photonic crystal straight waveguide with finite difference time domain method. Localized modes of photonic crystal waveguide are very different from those of photonic crystal with dot defect. For the propagation character of localized modes depends on the propagation...