Simulation and design of plasmonic directional couplers: application to interference-based all-optical gates

The paper is focused on the design of optical components based on plasmonic multi-slot directional couplers. In particular, the design of an all-optical gate is proposed, whose operation is based on the coupling between three plasmonic slots. The device input wavelength is 1550 nm, typical of long-haul telecommunication systems. The device footprint is as small as 11×6 µm 2 and the contrast ratio as an AND gate is about 5.8 dB. The two well-known Finite-Difference Time-Domain (FDTD) and Finite-Difference Eigenmode (FDE) methods are used for the device simulation and optimization.