Plasmonic Photovoltaic Double-Graphene Detector Integrated Into TiN Slot Waveguides

Abstract

Graphene has emerged as an ultrafast photonic material for on-chip photodetection. However, its atomic thickness limits its interaction with guided optical modes, which in turn weakens the photoresponse of waveguide-integrated graphene photodetectors. Nonetheless, it is possible to enhance the interaction of guided light with graphene by nanophotonic means. Herein, we propose a practical design of a plasmon-enhanced photovoltaic double-graphene detector that is integrated into 5 $\mu$m long titanium nitride slot waveguides. The use of double-graphene in this configuration yields a high responsivity of 2.18 A/W and more for a 0.5 V bias, across the telecom C-band and beyond. Moreover, the device operates at an ultra-high-speed beyond 100 GHz with an ultra-low noise equivalent power of $<\!35\,$pW/$\sqrt{\text{Hz}}$. The reported features are highly promising and are expected to serve the needs of next-generation optical interconnects.

Keywords

• Silicon photonics
• nanophotonics
• plasmonics
• photodetectors
• graphene
• 2D materials