The rate of advancement in digital communication may be hampered in the future by the amount of energy required to power it. Standard silicon photonics require energy an order of magnitude larger than is currently available. Energy efficient graphene-based optoelectronics promise to address this.
[Image source: Cambridge - Dr. Ilya Goykhman]
The use of standard metal-based electronics in telecommunications has been challenged by optical communications in recent years - but the new technology is not without its issues. In order to increase the range of detectable data in the electromagnetic spectrum, the industry has integrated germanium absorbers with standard silicon photonic devices. Now, researchers have identified a simpler approach to the production of highly responsive photodetectors.
In research conducted by an international collaboration of universities, scientists have integrated graphene with silicon to achieve 0.37A/W responsivity at 1.55μm using avalanche multiplication. 'This is a significant result which proves that graphene can compete with the current state of the art by producing devices that can be made more simply, cheaply and work at different wavelengths. Thus paving the way for graphene integrated silicon photonics,' reported co-author Professor Andrea Ferrari, director of the Cambridge Graphene Centre and Chair of the Management Panel of the Graphene Flagship.
Dr Ilya Goykhman, lead author and Senior Research Associate in the Cambridge Graphene Centre, said: 'The vision here is for graphene to play an important part in enabling optical communication technologies. This is a first step towards this, and, over the next two years the aim of the wafer-scale integration and optoelectronics work-packages of the Flagship is to really make this happen.'
Professor Ferrari heads the Graphene Flagship, one of Europe’s first 10-year Future and Emerging Technologies (FET) flagships, with the mission of bringing research in graphene from academia into society. He explained:
'Graphene can beat current silicon photonic technology in terms of energy consumption. The Graphene Flagship is investing a lot of resources into wafer-scale integration with the creation of a new Work Package. We have identified a vision, where graphene is the backbone for data communication, and we plan to have a telecommunication bank capable of transferring 4x28 GB/s by 2018. The research in this Nano Letters paper is the first step towards achieving that vision, the importance of which is clearly recognised by companies such as Ericsson and Alcatel-Lucent who have joined the Flagship to help develop it.'
Further work is required, Professor Ferrari said: 'We have shown the potential for the detector but we also need to produce a graphene-based modulator to have a full, low energy optical telecommunication system and the Flagship is working hard on this problem. The Flagship has collected the right people in the right place at the right time to work together towards this goal. Europe will be at the cutting edge of this technology. It is a great challenge, and a great opportunity for Europe, as there is such high added value to the devices it will be cost effective to manufacture the device in Europe - keeping the value of the technology within the European community.'
Read the team's research findings here.
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Written by Jody Binns