Graphene-based terahertz waveguide modulators

We report two proof-of-principle designs of silicon terahertz (THz) modulators based on guiding structures wherein graphene is introduced to actively control the properties of the waveguides, thus tuning their transmissivity. Using well-established models to characterize the electromagnetic parameters of electrically-doped graphene, we estimate the theoretical performance of the proposed structures, in particular the required switching voltage and the achievable modulation depth. These results predict considerably improved performance with respect to the state-of-the-art of graphene THz modulators, together with reduced size and larger THz bandwidth.