Towards 100 GHz Waveguide Ge/Si Avalanche Photodiodes for High-Speed Optical Interconnects

Abstract

We report on the design, modeling, and measurements of high-speed, silicon-contacted, waveguide-coupled Germanium-on-Silicon (Ge/Si) avalanche photodiodes (APDs) fabricated on 300 mm Silicon On insulator (SOI) wafers. The devices achieve a peak 3-dB bandwidth (BW) exceeding 100 GHz and maintain 70 GHz BW at a responsivity of 2 A/W in both the O- and C-bands, at a relatively low reverse bias of 7 V. These results demonstrate the strong potential of Ge/Si APDs to be used for next-generation short-reach optical interconnects targeting 400 Gbps per lane operation.