2D photonic crystal hexagonal ring resonator-based all-optical logic gates

Abstract

This paper proposes a novel and compact design of two-dimensional photonic crystal (PhC) based all-optical logic gates with a unique combination of line defects and ring resonator. The proposed design comprises air holes in a Si background arranged in hexagonal lattice geometry. The finite difference time domain (FDTD) and plane wave expansion (PWE) methods are used to analyze and calculate the required performance metrics. The peculiar property of the proposed structure is that the same structure is used for the realization of all All-optical logic gates and is symmetric about the origin. The principle operation used is the linear interference method in which the phase of the input beams is kept at φ=00 while the appropriate phase is introduced at the additional port known as reference port R so that they may interfere constructively or destructively. The All-Optical logic gates implemented using a proposed single structure are AND, OR, XOR, NOT, NAND, XNOR, and NOR, showing an ON to OFF contrast ratio of 12 dB, 20.63 dB, 4.44 dB, 2.07 dB, 4.44 dB, 12 dB, and 6.05 dB respectively. Moreover, AND, OR, and XNOR gate offers a response period of 0.353 ps and a bit rate of 2.83 Tb/s.