Silicon Electro-Absorption Modulator Based on Graphene-Hexagonal Boron Nitride Heterostructure

Graphene, a monolayer of carbon atoms, is one of most interesting optical materials in nanoscale photonics because its unique optoelectronic properties have allowed us to develop fast and broadband photonic devices. Electro-optic modulators have been designed with graphene to improve their performance and to more precisely understand their operating principles. To expand the applications of photonic device design, here we propose a silicon electro-absorption modulator, based on a graphene-hexagonal boron nitride heterostructure. The optical characteristics of the proposed modulator were numerically investigated considering an anisotropic and an isotropic graphene model. In the anisotropic graphene model, the light absorption by graphene is based on the Pauli blocking principle, while graphene's epsilon-near-zero effect is dominant in the optical power modulation under the isotropic graphene model. We performed optimization of the key structural parameters to achieve satisfactory modulation characteristics.