Transmission analysis and applications of bended waveguides in hexagonal photonic crystals

Transmission of light through linear defects in two-dimensional (2D) photonic crystals has been already successfully demonstrated in two ways: numerical simulations and experimental measurements. Recently, novel waveguides have been proposed in which the propagation of photons is performed via hopping due to overlapping between nearest-neighbors defect cavities. These waveguides are commonly referred to as coupled-cavity waveguides (CCW). In this work, we present a comprehensive analysis of the light transmission (TM modes) in CCWs created in hexagonal 2D photonic crystals made of high-index dielectric rods. Numerical simulations of the transmission are performed using a 2D Finite-Difference Time-Domain method. A plane wave algorithm and a simple one-dimensional (ID) tight-binding model are employed to describe the miniband which allows the light transport. It is shown that modifying the individual cavities along the CCW one can control the average frequency and the dispersion relation of the miniband. The results also show that this novel guiding method can be used to develop 1310nm/1550nm Coarse-WDM optical demultiplexers employing bended waveguides.