An Ultra Small Optical Switch Design Based on Directional Coupler in Two-dimensional Photonic Crystals

We theoretically investigate an ultra small structure with directional coupler (DC) in a two dimensional (2D) photonic crystal (PhC)for realizing the switching phenomenon. In this design, triangular lattice of air holes in dielectric matrix is utilized. The DC is formed by creating two straight line defect waveguides, separated by single row of air holes. We showed that by adjusting the size of the air holes between both the two waveguides, the input signal beam can be switched to a different output ports with a response timeless than 2ps. Difference Time Domain (FDTD) technique is used to simulate the power-time switching curves. The advantages of this method are high stability and accuracy in computations. The total size of the proposed switch is 31.85μm² which is highly suitable for Photonic Integrated Circuits (PICs).