A novel design for an ultracompact optical majority gate based on a ring resonator on photonic crystal substrate

This paper explores the design and simulation of a majority gate with three inputs based on the resonance ring of 2D photonic crystals. The design of this gate uses a ring resonator and four waveguides in a square lattice. This structure is simple and small with dielectric rods of silicon on an air substrate. Low and high logics are defined based on the optical sources being on or off. The large interval between 0 and 1 at the output demonstrates the high accuracy of this optical gate. The operating wavelength of the gate is 1.55 mu m, which is in the photonic band gap calculated for the gate structure. Calculations are carried out in transverse magnetic (TM) mode using the finite-difference time-domain (FDTD) numerical method.