Double-layer graphene optical modulator.

Here we report a high-performance double-layer graphene optical modulator. By using two graphene layers and an oxide layer in between to form a p-oxide-n like junction, this modulator operates at 1 GHz with a high modulation depth (~0.16 dB/μm) at a moderate drive voltage (~5 V). Benefited from the symmetrical band structure of graphene near Dirac point, such design eliminates the optical loss widely existing in silicon photonics and has advantages including small footprint, low energy consumption, and low insertion loss.