Photo thermal effect graphene detector featuring 105 Gbit s\u22121 NRZ and 120 Gbit s\u22121 PAM4 direct detection

S Marconi,V Sorianello,W Templ,V Mišeikis,S Tirelli,F Buchali,S Soresi,P Galli,C Coletti,A Montanaro,M Romagnoli,M A Giambra

doi:10.1038/s41467-021-21137-z

Abstract

One of the main challenges of next generation optical communication is to increase the available bandwidth while reducing the size, cost and power consumption of photonic integrated circuits. Graphene has been recently proposed to be integrated with silicon photonics to meet these goals because of its high mobility, fast carrier dynamics and ultra-broadband optical properties. We focus on graphene photodetectors for high speed datacom and telecom applications based on the photo-thermo-electric effect, allowing for direct optical power to voltage conversion, zero dark current, and ultra-fast operation. We report on a chemical vapour deposition graphene photodetector based on the photo-thermoelectric effect, integrated on a silicon waveguide, providing frequency response >65 GHz and optimized to be interfaced to a 50 Ω voltage amplifier for direct voltage amplification. We demonstrate a system test leading to direct detection of 105 Gbit s−1 non-return to zero and 120 Gbit s−1 4-level pulse amplitude modulation optical signals.

Highlights

One of the main challenges of generation optical communication is to increase the available bandwidth while reducing the size, cost and power consumption of photonic integrated circuits
Typical Si photonics transceivers may include: modulators based on Si junctions realized by implantation doping[9], modulators based on germanium (Ge) or silicon-germanium (SiGe) epitaxy[10,11], photodetectors based on Ge epitaxy[12]
In refs. 54,55 we demonstrated the high speed of operation the PTE detector integrated on a silicon nitride (SiN) waveguide using poly-vinyl alcohol (PVA) as gate dielectric

Summary

Introduction

One of the main challenges of generation optical communication is to increase the available bandwidth while reducing the size, cost and power consumption of photonic integrated circuits. Waveguide integrated graphene detectors based on PTE effect have been reported in recent years showing voltage responsivity in the range 3.5–28 V W−1 49–53.

Results

Conclusion