World Record in Wireless Terahertz Transmission: Fraunhofer HHI achieves 221.5 Gb/s over 500 meters in Berlin

Researchers from the Photonic Networks and Systems Department at Fraunhofer Heinrich Hertz Institute (HHI) have set a new world record for wireless data transmission in the terahertz range. Over a real-world free-space distance of 500 meters in the heart of urban Berlin, the team achieved a measured net data throughput of 221.5 Gb/s in the 300-GHz band. The corresponding paper was presented at the Optoelectronics and Communications Conference (OECC) 2026, one of the world’s leading conferences in the field of optical communications, where it received the Best Student Paper Award.

The demonstration was carried out in close collaboration with Fraunhofer IAF, the Berlin University of Applied Sciences (HTW), and the Technical University of Berlin. The award-winning paper is titled:

Record 221 Gb/s Dual Polarization THz Wireless Transmission Over 500 m Using PCS-64QAM at 300 GHz

The record was made possible by combining probabilistic constellation shaping with dual polarization and 64QAM (PCS-DP-64QAM) with high-performance amplifiers. By specifically adapting the source entropy to the signal-to-noise ratios of the 500-meter link, the team achieved significantly higher spectral efficiency. Terahertz links act like an invisible radio bridge that carries data volumes similar to those of fiber optics—but without cables buried in the ground. As so-called “wireless fiber extenders,” they are intended to connect future 6G networks to the optical transport network in areas where laying fiber-optic cables is too expensive or technically impossible. Key results include:

• A measured net data throughput of 221.5 Gb/s over 500 meters in the 300-GHz band.
• A doubling of the previous state-of-the-art performance at a distance of 500 meters.
• The world’s first rate-distance product exceeding 100 Tb/s·m in the 300-GHz band.
• Demonstration on a real outdoor line-of-sight route in an urban area under real atmospheric conditions.

The work was funded by the Federal Ministry of Research, Technology, and Space (BMFTR) as part of the SUSTAINET project under grant number 16KIS2272. The goal of SUSTAINET is to develop sustainable and high-performance network architectures for future generations of mobile communications.