Study on Omnidirectional Reflection Bands of Two-Dimensional Photonic Crystals and Optical Waveguides Based on This Effect

The omnidirectional reflection bands of several typical 2-D photonic crystals are presented. Numerical results show that there are omnidirectional reflection bands in photonic crystals without bandgaps. Furthermore, photonic crystal waveguides based on omnidirectional reflection bands can be constructed by using photonic crystals without bandgaps. Like conventional photonic crystal waveguides based on bandgaps, the novel waveguides can also achieve high-efficient transmission through waveguide bends with near-zero radii of curvature. This waveguide is expected to be applied to highly dense photonic integrated circuits after further research. The aforementioned results are helpful to widen the research field of photonic crystal waveguides.

I. Introduction

Photonic Bandgaps (PBGs) are the most important characteristic of photonic crystals (PCs) [1], [2]. Various applications of PCs have close relation with PBGs. For example, when a line defect is introduced into a bulk PC with PBGs, the defect modes, whose frequencies are restricted within PBGs, would occur, and line-defect photonic crystal waveguides (PCWs) can be constructed [3]. Now, almost all PCWs are constructed by PCs with PBGs.