Graphene photodetectors set speed record

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Data rates of up to 100Gbit/s in ultrafast photodetectors have been reported by researchers from the Graphene Flagship working at TU Vienna, Austria and AMO, Germany. The scientists claim the photodetectors have the highest bandwidth for graphene-based devices.

Simone Schuler, a researcher at TU Vienna, pictured, explained the importance of increasing data capabilities. “These kinds of photodetectors are typically used in optical data links, which form the backbone of the internet. The maximum operation speed of a photodetector defines the maximum data rate the detector can receive. So, the faster the photodetector, the more data it can receive.”

The photodetector is said to be highly sensitive, supposedly due to its compact structure. This enables its use alongside other optoelectronic devices, including switches in dense, integrated chips.

“This could open the path towards a complete integration on one CMOS chip. Graphene will be the enabling material for realising high performance photodetectors on a silicon platform,” added Schuler.

In the photodetectors, light is guided into a slot waveguide that is covered with graphene. Under specific electrical conditions in the graphene, the light in the waveguide generates a current in the graphene via the photothermoelectric effect, converting light into an electrical signal. The sensitivity of the detector can be tuned electrically without compromising the speed, enabling the high bandwidth and ultrafast data rate.