Coupling In 2-D Photonic Crystal Defects And Design Of Optical Switch

The dielectric constant of photonic crystal arranges periodically in space, its most notable feature is the photonic band gap and the local characteristics, light wave in the band gap can not be transferred, and it can control the movement of photon as semiconductor to electron. The line defect and point defect by removing the rods in perfect photonic crystals are two basic components to constitute a variety of optoelectronic devices. As photonic crystal optical devices with advantages of compact, easy integration and low loss transmission, it has developed quickly in recent years. Coupling between waveguides can change the direction of the transmission. Introducing the heterogeneous structure in the coupling region can achieve the independence of the optical switching function. The main works in this article are as follows:1. The relation between PBG of two kinds of structures for TE polarization r is investigated. And the distributions of two dimensional PCs defect state are also studied. We simulate the point defect of the square and triangular photonic crystal; calculating the resonant frequency, which provide convenience to the design of the filter.2. According to the coupled mode theory, calculate the coupling length between the waveguides and design the directional couplers. By analyzing the coupling properties between waveguides and selecting different transmission direction, different WDM system based on photonic crystal waveguides can be designed.3. We firstly study the coupling effect between photonic waveguide and micro-cavity, and according to the time-domain coupled mode theory and guided mode computation resonance theory, and calculated by simulation the cavity center frequency. Then calculate the interaction of the resonator and waveguide to get the high quality factor of the filter structure.4. Establishing a optical switch mode based on directional waveguide by two adjacent and parallel waveguides. Firstly, discuss and analyze the optical switching characteristic then by introducing the heterogeneous structure, using finite different time domain to analyze the switching effect by changing the heterogeneous coupling waveguides. The result shows the coupling of the heterogeneous coupling waveguide is independent; the position of the heterogeneous structure doesn't change the optical switch function.