A Graphene-On-Gap Modulator With High Modulation Efficiency

We propose a high efficient graphene-on-gap modulator (GOGM) by employing the hybrid plasmonic effect, whose modulation efficiency is similar to 8-folds larger than that of present graphene-on-silicon modulator (GOSM) (similar to 0.1 dB / mu m). The proposed modulator has the advantage of short modulation length similar to 3.6 mu mm, relatively low insertion loss similar to 0.32 dB and larger modulation bandwidth similar to 0.48 THz. Moreover, an efficient taper coupler has been designed to convert the quasi transverse electric (TE) mode of conventional silicon waveguide to the hybrid plasmonic mode of GOGM, with a high coupling efficiency of 91%. This study may promote the design of high-performance on-chip electro-optical modulator.