Fraunhofer HHI and IAF demonstrate wireless terahertz transmission over a distance of one kilometer

Press release from Fraunhofer HHI /

Fraunhofer HHI, in collaboration with Fraunhofer IAF, has succeeded in using a THz transmission system to transmit 56 GBit/s wirelessly over a free space distance of 1 km. The transmission took place at a carrier frequency of 300 GHz. The transmission system used consists of a high-performance terahertz modem with signal processing algorithms from Fraunhofer HHI and fast, indium gallium arsenide-based integrated electronic high-frequency circuits from Fraunhofer IAF.

Dr.-Ing. Robert Elschner, head of the internal terahertz research activities in the department Photonic Networks and Systems at Fraunhofer HHI, explains: “For the first time, we were able to demonstrate that our THz transmission system can be used outside the laboratory and for transmissions over longer distances. In this way, we were able to gain first important insight into the stable operation of the system under the influence of atmospheric attenuation.” The experiments took place on a test track starting from a balcony at Fraunhofer IAF in Freiburg.”This is another important step towards a marketable THz transmission system“, comments Dr. Colja Schubert, head of the corresponding research group in the department of Photonic Networks and Systems. According to Dr. Schubert, the next planned step to win a larger clientele for terahertz technology is the construction of a weatherproof prototype. Another landmark is the demonstration of a real-time link over 1 km with a data rate of 100 Gbit/s, and the embedding in a fiber optic test network.

The seamless fiber optic connection of a 100 Gbit/s THz real-time transmission system on a laboratory scale was already presented to an expert audience this year at EuCNC (European Conference on Networks and Communications) and ECOC (European Conference on Optical Communication). ”The unique possibility to integrate free-space THz transmission systems into existing fiber optic networks without an additional digital interface will lead to an immense improvement in the network access of all users,” says Dr.-Ing. Thomas Merkle, head of development activities for fast terahertz circuits at Fraunhofer IAF.

The transmission uses frequencies far above the 4G LTE/5G mobile communication frequencies and is therefore an ideal complement to existing technologies. Bandwidth requirements will continue to rise in future communication networks, driven by new applications such as industry 4.0, autonomous driving, AI-based cloud/edge computing, eHealth, smart cities, and Virtual and Augmented Reality. Thus, wireless terahertz technology is an important cornerstone of future communication networks.

The work on the THz technology at Fraunhofer is being promoted to market maturity both within the framework of in-house research projects and together with international partners in the publicly funded EU project TERRANOVA.

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