Three output port channel-drop filter based on photonic crystals

We present a photonic-crystal (PC) channel-drop filter (CDF) design based on 3x3 PC ring resonators. The normalized transmission spectra for single-ring and dual-ring configurations have been investigated using two-dimensional finite-difference time-domain (FDTD) technique in a square-lattice dielectric-rod PC structure. First, we investigate a single ring and we show that backward and forward dropping is possible in the third communication window. Then we add another ring and waveguide to develop a new CDF. This filter consists of an input and three outputs. Our FDTD simulation yields more than 85% efficiency over each output port.