(Frankfurt am Main, November 5, 2025) The Johann Philipp Reis Prize is awarded every two years to young scientists who have made significant innovations in communications engineering. Yesterday, Prof. Dr. Georg Rademacher received the award at a ceremony in Gelnhausen, Hesse. Dr. Werner Mohr, one of the award judges, emphasizes the high relevance of Rademacher's research: "Digitalization and artificial intelligence hold great potential for increasing efficiency in society and the economy. To leverage this potential, we need extremely powerful transmission systems. That is why the research of Prof. Dr.-Ing. Georg Rademacher is so important, because it shows how immensely the capacity of fiber optic technology can be increased through processes such as space division multiplexing (SDM)."
The prize, worth EUR 10,000, is sponsored by the Hessian municipalities of Gelnhausen and Friedrichsdorf, where the inventor and namesake Reis lived, as well as Deutsche Telekom AG and the Information Technology Society within the VDE (VDE ITG).
Space division multiplexing: Parallel tracks on the data highway
Transmitting more data via fiber optics – that is the research motto of Prof. Dr.-Ing. Georg Rademacher. Since the first commercial use of fiber optic networks for data transmission in the 1980s, measures have been taken to increase their capacity. However, in 2010, a research project determined that conventional fiber optics reach their limits at around 100 terabits per second. "At the same time, it became clear that we will need solutions in the future to transmit much more data," explains the expert in optical communications engineering. "Of course, it would be possible to work with several parallel systems, but that would be expensive, energy-intensive, and, in some applications, not feasible at all due to space constraints."
At the Technical University of Berlin, Rademacher began researching new types of fiber optics with multiple cores (multicore fibers) or with one core with multiple modes (multimode fibers). "Space division multiplexing is always about transmitting different data in parallel in a single fiber and making the best possible use of the available space – basically like a multi-lane highway."
World records and the path to practical application: From Japan to Stuttgart
After moving to Japan, Rademacher was able to carry out large-scale system demonstrations at the National Institute of Information and Communications Technology (NICT), one of the best-equipped laboratories for optical communications technology in the world. "We achieved a data rate of 3.5 petabits per second (3,500 Tb/s) in a mode-multiplex transmission—a value that has never been measured in a fiber optic cable with a standard cladding diameter. Combined multimode and multicore transmission even achieved 10.6 petabits per second (10,600 Tb/s)."
With such world records, Rademacher and his colleagues attracted a great deal of attention in the professional world, but he was ultimately drawn back to the practical implementation of his research. Since 2023, he has headed the Institute for Electrical and Optical Communications Engineering at the University of Stuttgart and has launched several consortium projects in Germany to develop practical application scenarios for modern fiber optics. He is also keeping an eye on cutting-edge developments such as hollow-core fibers, in which light propagates at nearly the speed of light. "We'll see how quickly this can be realized – but with the AI boom and the data centers it requires, providing the highest data rates is one of the topics of the future."
About the award winner
Prof. Dr.-Ing. Georg Rademacher studied electrical engineering at the Technical University of Berlin and graduated with a diploma in 2011. After completing his dissertation at the TU Berlin in 2015, he worked as a scientist at the National Institute of Information and Communications Technology (NICT) in Japan from 2016 to 2023. Since April 2023, he has held the Chair of Integrated Photonic Systems at the University of Stuttgart, where he is also Director of the Institute for Electrical and Optical Communication Engineering ( ). He also heads the "Space-Division Multiplexing" working group at the Fraunhofer Heinrich Hertz Institute in Berlin. Rademacher has already received numerous awards, such as the ITG Prize 2017 and the Maejima-Hisoka Prize 2020, and in addition to his research work, he is active in program committees (OFC, ECOC, CLEO, SPPCOM) as well as the IEEE and VDE ITG. As an associate editor at OPTICA, he contributes to supporting the community with high-quality scientific publications.
About the Johann Philipp Reis Prize
Johann Philipp Reis was born in Gelnhausen in 1834 and died in Friedrichsdorf (Hesse) in 1874. The physicist and inventor is considered a pioneer of the telephone thanks to his development of a method for transmitting sound via electrical lines. The Johann Philipp Reis Prize has been awarded regularly every two years since 1986. It is aimed at scientists up to the age of 40. The prize is awarded for significant innovations in communications technology that have had or are expected to have an impact on the economy. The winners are selected by experts from the Information Technology Society within the VDE.
