Les ondes térahertz au secours de l’Internet sans fil

Despite the expansion of the 4G network, wireless Internet still needs a great deal of innovation if it is to achieve the same speeds as fibre optics. An international team, based at the Institute of Electronics, Microelectronics and Nanotechnology, has shown that waves in the terahertz frequency range could take over from wired networks. This work is published in Nature Photonics.

IEMN (A. Duchêne) - Visual illustration of the main component, i.e. the component that makes it possible to "switch" from the world of optical fibres (bottom left) to the world of terahertz (the spiral) for telecoms (small shapes top right).

In 2018, the Internet will account for more than 130 billion billion bytes of data exchanged per month. Since most of this growth is expected on wireless channels, ultra high-speed transport infrastructures will have to evolve considerably. This requires faster components, because the increase in throughput will only be absorbed if the frequency of the waves rises towards the beginning of the THz band (between 220 and 350 GHz). Researchers at the Institute of Electronics, Microelectronics and Nanotechnology (IEMNCNRS/Université Lille-1/ISEN Lille/Université de Valenciennes et du Hainaut-Cambrésis/École Centrale de Lille) were able to set up an initial demonstrator, based on optoelectronic devices that transform optical fibre signals into radio signals.

These demonstrations use optoelectronic components that perform 'photomixing'. In this process, two lasers are sent to the same photodiode, which transforms them into a signal corresponding to the difference in their wavelengths. This converts optical signals of the order of a hundred THz, typical of optical fibres, into a radio signal of around 300 GHz. At the IEMN, a wireless data rate of 32 Gbit/s was transmitted over several tens of metres using a frequency of around 400 GHz. These frequencies offer a very good compromise between the capacity of the components and the attenuation of the waves in the air, which will eventually make it possible to achieve the range required for urban use. This step will enable us to move towards the next challenges: transfer speeds in excess of 100 Gbit/s and transmissions over more than a kilometre.

The technology associated with this work has been developed thanks to the network of major technology centres. RENATECH network.with the help of laboratories PhLAM and IRCICA and support from the ANR COM'TONIQ programme, the Equipex FLUX, Excelsior and the CPER Photonics for society.

References :

Advances in terahertz communications accelerated by photonics,
T. Nagatsuma, G. Ducournau and C.C. Renaud
Nature Photonics - 10, 371-379 (2016)
DOI: 10.1038/NPHOTON.2016.65

Contacts chercheurs :
Guillaume Ducournau – IEMN
Contact communication INSIS :
insis.communication@cnrs.fr

Les ondes térahertz au secours de l’Internet sans fil

Despite the expansion of the 4G network, wireless Internet still needs a great deal of innovation if it is to achieve the same speeds as fibre optics. An international team, based at the Institute of Electronics, Microelectronics and Nanotechnology, has shown that waves in the terahertz frequency range could take over from wired networks. This work is published in Nature Photonics.

IEMN (A. Duchêne) - Visual illustration of the main component, i.e. the component that makes it possible to "switch" from the world of optical fibres (bottom left) to the world of terahertz (the spiral) for telecoms (small shapes top right).

In 2018, the Internet will account for more than 130 billion billion bytes of data exchanged per month. Since most of this growth is expected on wireless channels, ultra high-speed transport infrastructures will have to evolve considerably. This requires faster components, because the increase in throughput will only be absorbed if the frequency of the waves rises towards the beginning of the THz band (between 220 and 350 GHz). Researchers at the Institute of Electronics, Microelectronics and Nanotechnology (IEMNCNRS/Université Lille-1/ISEN Lille/Université de Valenciennes et du Hainaut-Cambrésis/École Centrale de Lille) were able to set up an initial demonstrator, based on optoelectronic devices that transform optical fibre signals into radio signals.

These demonstrations use optoelectronic components that perform 'photomixing'. In this process, two lasers are sent to the same photodiode, which transforms them into a signal corresponding to the difference in their wavelengths. This converts optical signals of the order of a hundred THz, typical of optical fibres, into a radio signal of around 300 GHz. At the IEMN, a wireless data rate of 32 Gbit/s was transmitted over several tens of metres using a frequency of around 400 GHz. These frequencies offer a very good compromise between the capacity of the components and the attenuation of the waves in the air, which will eventually make it possible to achieve the range required for urban use. This step will enable us to move towards the next challenges: transfer speeds in excess of 100 Gbit/s and transmissions over more than a kilometre.

The technology associated with this work has been developed thanks to the network of major technology centres. RENATECH network.with the help of laboratories PhLAM and IRCICA and support from the ANR COM'TONIQ programme, the Equipex FLUX, Excelsior and the CPER Photonics for society.

References :

Advances in terahertz communications accelerated by photonics,
T. Nagatsuma, G. Ducournau and C.C. Renaud
Nature Photonics - 10, 371-379 (2016)
DOI: 10.1038/NPHOTON.2016.65

Contacts chercheurs :
Guillaume Ducournau – IEMN
Contact communication INSIS :
insis.communication@cnrs.fr