Design and Simulation of a NAND Gate based on 2D Photonic Crystals

In this paper, we attempt to design and simulate an all-optical NAND gate using 2D photonic crystals. The proposed structure has 3 inputs and 1 output based on ring resonators. One of the inputs is used for the bias and 2 other inputs are the main inputs of the gate. We used line and point defects to guide the light from the inputs to the output. This structure is simple and small and consists of 19*19 silicon rods on an air substrate. This gate has a high accuracy because of the large difference between "1" and "0" logic, which is defined by the amount of power transferred from the inputs to the output. The contrast ratio (CR) for the proposed gate has been determined to be 7.14 dB. Calculations are performed out in the TM mode using the Plane Wave Expansion (PWE) and Finite Difference Time Domain (FDTD) methods to solve Maxwell's equations.