Graphene-Based Silicon Photonic Electro-Absorption Modulators and Phase Modulators

Since their first demonstration, graphene-based silicon waveguide modulators have evolved towards very attractive devices for adoption in future optical interconnects. In this paper, we first review state-of-the-art for graphene-based intensity modulators. Two important device configurations are considered: one using a single graphene layer, biased through the silicon waveguide itself and one using a capacitive stack of two graphene layers, which can be integrated on passive silicon and silicon nitride waveguides. We also discuss our recent work on fabricating such devices fully in a CMOS pilot line. In a next section, we review graphene-based phase modulators. Again, we compare the two types of modulators, involving a single or double graphene layer stack. In addition, we present new results, comparing modulators integrated on standard strip waveguides with modulators integrated on slot waveguides, which allow for a higher confinement of the optical field. Finally, we summarize our findings and present and outlook for the field, based on simulated results.