Keysight and researchers from France's Centre National de la Recherche Scientifique (CNRS), Lille University, and Osaka University have announced they had broken the 1 Tbps barrier. In a paper presented at the Asia-Pacific Microwave Conference, professors Guillaume Ducournau and Tadao Nagatsuma detailed this achievement using a system built with a combination of terahertz photodiodes and an electronics-based receiver covering a range of 500-724 GHz. In this frequency band, they used channel aggregation with 14 carriers and a range of 16 to 64 quadrature amplitude modulation (QAM) to achieve a total data throughput of 1.04 Tbps.
The demand for more cellar data and higher data throughputs is insatiable. The goal for 6G is to achieve data throughput rates 10 times faster than in 5G, eventually achieving up to 1 terabit per second (Tbps) throughput. This speed will enable use cases such as holographic communications and extended reality experiences that aren't possible with today's data speeds.
To reach 1 Tbps speeds, several tens or hundreds of gigahertz of bandwidth are needed, which makes higher frequencies like sub-terahertz (sub-THz) appealing. Currently, there is extensive research into creating early sub-THz communications systems, but components for these frequencies are still under development and very scarce.
"Terahertz communications have really been pushed forward in recent years, with interesting milestones reached using photonics or electronics," said Prof. Ducournau, who specializes in creating terahertz sources and receivers, and applying them to communications-related applications using photonics and photomixing. "I am excited to see that photonics enabled the first aggregated greater than 1 Tbps sub-THz system, as photonics technologies have accelerated to boost terahertz communication research."
"I am also so happy to reach a single-lane 1-Tbps data rate, that is a long-time dream of terahertz communication researchers," adds Prof. Nagatsuma.
Achieved data rates over terahertz frequencies
To measure the performance of their state-of-the-art system, they used a four-channel Keysight Infiniium UXR-series oscilloscope coupled with vector signal analysis (VSA) software. The figure above shows the measured performance of the carrier aggregated system in yellow between 500-724 GHz, with 14 total carriers. The measured performance of a single carrier at 632 GHz is shown in the figure below. The high performance of the UXR made these measurements possible. The four 70 GHz channels and wide supported voltage range made it possible to receive the full bandwidth of their signals. In addition, the large library of supported waveforms in the VSA allowed the researchers to demodulate their signals with ease to successfully measure the system throughput.
Measured throughput of signal carrier signal at 632 GHz with different modulations. 32-QAM / 40 GBaud (0.2 Tbps, left) and 16-QAM / 40 GBaud (160 Gbps, right).
"The combination of wideband terahertz photodiode, receiver and the unique performance of Keysight's UXR really enabled to succeed in these experiments," said Prof. Ducournau. "Their advanced instruments are really pushing forward our terahertz research."
Photonics is one new technology that is being investigated to enable communications at sub-THz bands. Whether or not photonics will be widely adopted in the future remains to be seen, but Keysight remains committed to providing the tools that researchers need to build the next generation of wireless communications devices.
The 6G research is supported by the France 2030 programs, PEPR (Programmes et Equipements Prioritaires pour la Recherche), CPER Wavetech, E.U. TERAOPTICS and by the Beyond 5G R&D Japan Promotion Program (00901) from the National Institute of Information and Communications Technology (NICT). The PEPR is operated by the Agence Nationale de la Recherche (ANR), under the grants ANR-22-PEEL-0006 (FUNTERA, PEPR 'Electronics') and ANR-22-PEFT-0006 (NF-SYSTERA, PEPR 5G and beyond - Future Networks). The Contrat de Plan Etat-Region (CPER) WaveTech is supported by the Ministry of Higher Education and Research, the Hauts-de-France Regional Council, the Lille European Metropolis (MEL), the Institute of Physics of the French National Centre for Scientific Research (CNRS) and the European Regional Development Fund (ERDF). The TERAOPTICS project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 956857.
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