Research On Band-gap Characteristics Of Two-Dimensional Photonic Crystal And Wavelength Splitter

Photons have advantages of fast transmission speed, big bandwidth, and weak interaction between themselves etc. Taking photons as the carrier of information, it can greatly improve information transmission speed, lower power consumption, and enhance anti-jamming capability and confidentiality. As a novel material, photonic crystal can effectively control the propagation of light in which the information carrier is photon. Photonic crystal is a kind of artificial materials in which dielectric materials with differing dielectric constant are replaced periodically in space. Its basic characteristic is photonic band gap (PBG). Electromagnetic waves whose frequencies are in PBG are prohibited. Through introducing line defect in photonic crystal, photonic crystal waveguide forms, which can achieve efficient light transmission and large angle of turn. Wavelength splitter is a very important component of integrated optical device. The rapid development of photonic crystal provides a new path toward high-integrated for wavelength splitter and other optical devices.The band gap characteristics of two-dimensional cylindrical photonic crystal was studied. For two typical structures, namely square lattice and triangular lattice structure, the effect of fill rate, refractive index difference between column and background on band gap is investigated respectively. On this basis, the transmission characteristics of photonic crystal waveguide are studied. The simulation results showed that either straight or curved waveguide has high transmission efficiency. Based on the study of photonic crystal waveguide, a three-port wavelength splitter is proposed. The simulation result showed that it can complete the separation of two wavelengths. In order to improve the efficiency of the three-port wavelength splitter, an optimized four-port wavelength splitter is presented, which can effectively separate three incident wavelengths.