LAUSR

In this paper, compact all-optical XOR and XNOR gates based on different configurations of metal–insulator–metal plasmonic ring resonators (PRRs) have been proposed. Square and octagon-shaped rings have been used in this case. The logic gates have been simulated using the two-dimensional finite-difference time-domain numerical method, with a  conventional perfectly matched layer as the absorbing boundary condition of the area under simulation. The phenomenon of Fano resonance is employed by the proposed gates to excite ON/OFF states. As a result, a large value of contrast ratio (C.R.) is obtained. The results show that the values of C.R. of XNOR and XOR gates for square-shaped PRR are 22.66 and 22.9 dB, respectively and the values of C.R. of XNOR and XOR gates for octagon-shaped PRR are 23.01 and 23.52 dB, respectively. Also, it is shown that the octagon-shaped gates have higher transmission ratios than other proposed configurations. The proposed optical logic gates can be used as key components in optical communications and for designing compact plasmonic devices.