Optimal design of 90° bend in two dimensional photonic crystal waveguides

Abstract

The aim of this contribution is to present the key factor that affect the transmission characteristics of the 90° bent photonic crystal waveguides. We propose a new type of two dimensional photonic crystal (2DPC) 90° bend waveguides. Within a single optimization step we already achieve very low power reflection coefficient over almost the entire frequency range of the Photonic Band Gap (PBG). A further analysis shows that there is a single critical rod in the optimized bend structure that exhibits an extraordinary high sensitivity at a given frequency. Using the Finite Difference Time Domain (FDTD) method and the absorbing boundary conditions proposed, we simulate its transmission characteristics and show an excellent transmission of light in 90° bend waveguides achieve 100% for several frequencies. This opens the door to novel topologies for compact switches and sensor applications. © 2008 Asian Network for Scientific Information.