%0 Journal Article %T High-speed waveguide-coupled graphene-on-graphene optical modulators %A Steven J. Koester %A Mo Li %J Physics %D 2012 %I arXiv %R 10.1063/1.4704663 %X An electro-absorption optical modulator concept based upon a dual-graphene layer is presented. The device consists of a silicon-on-insulator waveguide upon which two graphene layers reside, separated by a thin insulating region. The lower graphene acts as a tunable absorber, while the upper layer functions as a transparent gate electrode. Calculations based upon realistic graphene material properties show that 3-dB bandwidths over 100 GHz (30 GHz) are possible at near- (\lambda=1.55 \mu m) and mid- (\lambda=3.5\mu m) infrared bands. The effect of background doping and potential fluctuations on the bandwidth, modulation depth and insertion loss are also quantified. %U http://arxiv.org/abs/1202.4791v1