Waveguide-coupled hybrid plasmonic modulator based on graphene.

In this paper, we propose a low-transmission-loss, high-speed, graphene-based electro-absorption modulator with a hybrid plasmonic waveguide at 1.55 μm. In the proposed device, double-layer graphene is placed on top of the horizontal hybrid plasmonic waveguide to enhance the light-graphene interaction. The adjustment of the in-plane permittivity of the anisotropy graphene causes a significant modulation of the absorption at the operating bandwidth of 0.4 THz, with modulation length of 8.5 μm and modulator footprint of 1.6  μm². A taper silicon coupler is used for waveguide coupling, and 80% coupling efficiency is achieved. In addition, the modulation potential on a smaller footprint is further shown.