All-Optical XOR, XNOR, NAND and OR Logic Gates Based on Photonic Crystal 3-DB Coupler for BPSK Signals

Abstract

Abstract We propose a very compact structure for all-optical XOR, XNOR, NAND and OR logic gates based on photonic crystal 3-dB coupler in binary-phase-shift-keyed (BPSK) signals. The square lattice of dielectric rods in SiO2 background has been considered for photonic crystal structure. The photonic band gap (PBG) and light propagation simulations of proposed logic structure have been accomplished by plane wave expansion and finite difference time domain methods. The proposed structure can achieve logical function when the refractive index of all rods and substrate is fabricated with relaxed error tolerance within −0.005 to 0.005 from designed parameters. The proposed logic functions may potentially be used as key components in all-optical information networks for processing the BPSK signals.