Plasmonic Feynman Gate Based on Suspended Graphene Nano-Ribbon Waveguides at THz Wavelengths

In this paper, a plasmonic Feynman gate based on suspended graphene nano-ribbon waveguides at THz wavelengths is proposed and numerically investigated. The proposed plasmonic Feynman gate is composed of two cascaded microring resonators. The resonant states of microring resonators are flexibly controlled by tuning chemical potentials of graphene in rings, and thus, the logic operation results of Feynman gate can be performed successfully. Compared to the plasmonic Feynman gate based on graphene nano-ribbons deposited on the Si substrate and the plasmonic Feynman gate based on graphene nano-ribbons deposited on the SiO2/Si substrate, our designed plasmonic Feynman gate can have better extinction ratio and crosstalk. Calculation results exhibit that the extinction ratio is larger than 15.39 dB and the crosstalk is lower than -15.55 dB when input logic states of our designed device are `00', `01', `10,' and `11'.