Study on Electromagnetic Wave Propagation Characteristics in Cylindrical Photonic Crystal Waveguides with High-Index Cores

Abstract

Cylindrical photonic crystal waveguides (CPCWs) with high-index cores are first proposed and analyzed by accurate full-vector finite difference method and finite-difference time-domain approach. The high-index core can be realized by inserting materials with higher refractive index values than normal pure-silica glass, for example, carbon dioxide, Liquefied Petroleum Gas (LPG), and nitrous oxide into the CPCW. It is generally observed that the high refractive index variation is not linearly changing with the normalized propagation constant. More significant discontinuities in field distributions are also noticed at dielectric boundaries for the CPCW with lower refractive index core, compared to the CPCW with higher-index core, which reasonably means that electromagnetic energy is more tightly confined for the CPCW design with higher-index core.