Photonic crystals (PCs) have many potential applications because of their ability to control light-wave propagation. In this paper, the influence of interaction region of elliptical pillars on a directional photonic crystal waveguide coupler is studied by solving Maxwell's equations with use of finite-difference time-domain method. The PC waveguide coupler introduced two rows of elliptical pillars in the interaction region. Introducing elliptical pillars in the interaction region can reduce the coupling length of PC waveguide coupler. The coupling length of PC waveguide coupler was changed by rotating the rotation angle of elliptical pillars. These results may provide novel application in photonic integrated circuits.
Physica E: Low-dimensional Systems and Nanostructures 28(2), pp.185-190