Analysis of coupling in two dimensional photonic crystal waveguides

The behaviour of a straight two-dimensional photonic crystal waveguides is analysed. Considering the two guides as a single system, we implement a photonic crystal directional coupler with micrometer dimensions. By fitting the interaction region separating the waveguide cores, composed of dielectric rods, we demonstrate that a suitable designing of the geometry of the interaction region separating the waveguide cores, composed of dielectric rods allows a more efficient coupling. We show that with only one row between the two parallel waveguides either than two rows, we can reduce the coupling length and increase the coupling coefficient of coupler.