All-optical design for multiplexer and comparator utilizing hybrid plasmonic waveguides.

Two optical combinational logic circuits, namely a 2×1 multiplexer and a comparator utilized by hybrid plasmonic waveguides, have been designed, analyzed, and simulated standing on the finite element method (FEM) with a COMSOL software package version 5.5. Transmission at the output port versus a wavelength range from 800 to 2000 nm, the contrast ratio, the modulation depth, and the insertion loss are the aspects used to estimate the circuits' functionality. The realization of these circuits was based on the fundamentals of the constructive and destructive interferences among the input and the biasing ports. The multiplexer circuits require a single substructure with a measurement of 400×400 and delivers the best transmission of 202.3% and 99.75% as a modulation depth, while the comparator performed by three substructures with a 1300×400 overall size offers a 202.6% as the best transmission and 99.99% modulation depth in the Equality situation. The operating wavelength and the magnitude of the transmission threshold are 1310 nm and 0.3, respectively.