100 GHz Plasmonic Photodetector

TLDR

Photodetectors compatible with CMOS technology have shown great potential in implementing active silicon photonics circuits, yet current technologies are facing fundamental bandwidth limitations. The study proposes and demonstrates a plasmonic photodetector that achieves record‑high bandwidth beyond 100 GHz, 36 % internal quantum efficiency, and a low footprint. The detector uses a photoconductive plasmonic‑Germanium waveguide that confines optical energy sub‑wavelength, providing short carrier drift paths and a low RC product, while the plasmonic structures with absorbing semiconductors enable efficient, high‑speed photodetection. The device achieves bandwidth beyond 100 GHz, 36 % internal quantum efficiency, and 72 Gbit/s data reception, indicating a cost‑efficient, CMOS‑compatible photodetector suitable for >100 Gbit/s applications in communications, microwave photonics, and THz technologies.

Abstract

Photodetectors compatible with CMOS technology have shown great potential in implementing active silicon photonics circuits, yet current technologies are facing fundamental bandwidth limitations. Here, we propose and experimentally demonstrate for the first time a plasmonic photodetector achieving simultaneously record-high bandwidth beyond 100 GHz, an internal quantum efficiency of 36% and low footprint. High-speed data reception at 72 Gbit/s is demonstrated. Such superior performance is attributed to the subwavelength confinement of the optical energy in a photoconductive based plasmonic-germanium waveguide detector that enables shortest drift paths for photogenerated carriers and a very small resistance-capacitance product. In addition, the combination of plasmonic structures with absorbing semiconductors enables efficient and highest-speed photodetection. The proposed scheme may pave the way for a cost-efficient CMOS compatible and low temperature fabricated photodetector solution for photodetection beyond 100 Gbit/s, with versatile applications in fields such as communications, microwave photonics, and THz technologies.