Graphene-aluminum oxide metamaterial for a compact polarization-independent modulator

Former study shows that the graphene-embedded modulator can only work in TE mode while cannot achieve enough extinction ratio in TM mode. However, an optical modulator which can work in both TE mode and TM mode is required by the mode multiplexing technology. By simply growing a graphene-aluminum oxide metamaterial layer on the silicon waveguide, an optical-absorption modulator which can achieve a large extinction ratio in both TE mode and TM mode is designed in this letter. In addition, our modulator can achieve a very compact footprint which is only 10 μm.