All-Optical Logic Gates Using a Plasmonic MIM Waveguide and Elliptical Ring Resonator

Abstract All - optical logic gates OR, XOR, AND and NOT based on two - dimensional ( 2D ) plasmonic metal - insulator - metal ( MIM ) coupled with Elliptical Ring Resonator ( ERR ) are presented , simulated and investigated by using the numerical method of the FEM (finite elements method ). The results are compared and validated with the finite difference time domain ( FDTD ) method . The proposed logic gates are achieved with the same structure using the constructive and destructive optical interferences between a control signal and input signal(s). Their characterization was mainly done for two spectral regions , visible and near - infrared . A high intensity contrast ratios (CR) between the logic states ( “1” and “0” ) can be achieved (28 dB ) at these spectral regions . We introduce a new parameter , "gap- threshold ratio ( GTR )", to characterize the gap between the maximum and minimum of the transmitted signal intensity for all logic gates. The suggested value of transmission threshold between logic 0 and logic 1 states is T th =0.2 . A comparison of the two parameters , (CR) and ( GTR ), with previous works shows that the proposed structure gives very good results for all logic gates configurations. The proposed all- optical logic gates configuration can be a key components in optical processing and telecommunication devices .

Abstract All optical logic gates are building blocks for all optical data processors. One way of designing optical logic gates is using threshold switching which can be realized by combining an optical resonator with nonlinear Kerr effect. In this paper we showed that a novel structure consisting of nonlinear photonic crystal ring resonator which can be used for realizing optical NAND/NOR and majority gates. The delay time of the proposed NAND/NOR and majority gates are 2.5 ps and 1.5 ps respectively. Finite difference time domain and plane wave expansion methods were used for simulating the proposed optical logic gates. The total footprint of the proposed structure is about 988 μm2.