Wireless data transmitted at 100Gbit/s

"Our project focused on integration of a broadband radio relay link into fibre optical systems," said Professor Ingmar Kallfass. In the experiment, radio signals were generated optically, with several bits combined using data symbols and transmitted at the same time. The transmitter generates the signals using an ultra broadband photon mixer, in which two optical laser signals of different frequencies are superimposed on a photodiode. The electrical signal was then radiated via an antenna. "It is a major advantage of the photonic method that data streams from fibre optical systems can be converted directly into high frequency radio signals," said Professor Jürg Leuthold. "This advantage makes the integration of radio relay links of high bit rates into optical fibre networks easier and more flexible." Data was received using active integrated electronic circuits. In the experiment, a semiconductor chip produced by the Fraunhofer Institute of Applied Solid State Physics (IAF) was used. The device is based on high-electron-mobility transistors (HEMT), enabling the fabrication of active, broadband receivers for the frequency range between 200 and 280GHz. "By transmitting multiple data streams simultaneously and by using multiple transmitting and receiving antennas, the data rate could be multiplied," says Swen König from the KIT Institute of Photonics and Quantum Electronics. "Hence, radio systems with a data rate of 1Tbit/s appear to be feasible."