Ultrahigh-modulation-efficiency graphene-silicon micro-ring modulator

Abstract Electro-optic (E/O) modulators are crucial for optical communication but face a trade-off between modulation bandwidth and efficiency. A small footprint could reduce the capacitance and increase the bandwidth. However, this usually results in low modulation efficiency. We address this trade-off by embedding a partially overlapped double-layer graphene on a silicon slot waveguide into an integrated micro-ring modulator. The modulator achieves a modulation bandwidth exceeding 40 GHz with an ultrahigh modulation efficiency of 10.99 V -1 µm -1 , which is an order of magnitude higher than state-of-the-art E/O modulators. We also demonstrate high reproducibility of the graphene modulator. The compact, highly efficient, and highly reproducible graphene E/O modulator has the potential to enable large-scale graphene photonic integrated circuits, facilitating a broad range of applications such as optical interconnects, optical neural networks, and programmable photonic circuits.