New World Record for Wireless Optical Transmission

Italian and Japanese scientists have demonstrated a laser based wireless communications system which has achieved a record transmission of 1.28 Terabit/s (or 1280 Gigabit/s) in a free air link between two transceivers installed on the roof of the CEIIC building and on the roof of the Building A at the Italian National Research Council around 210 meters away.

The experiment was carried out by a team from the Centre of Excellence for Information Engineering and Communication (CEIIC) of the Sant'Anna School of Advanced Studies in Pisa in collaboration with their Japanese partners from the National Institute of Information and Communications Technology (NICT) and Waseda University.

The optical communication system was set up with two transparent Free Space Optics antennas between an ultra-wide band fiber link and optical transmission in the air. The two antennas, placed high up, were not subject to interruptions due to people or cars passing.

"The 1.28 Terabit/s optical data traffic was generated in the CEIIC laboratory on the first floor then transmitted to the terrace of the same building through a fiber optic link and transparently connected to one of the antennas that sent the signals into the air (wireless - free space optics). In the second building this signal is collected from the second antenna directly to another fiber and then looped back through the same apparatus to the first one and then returned back in fiber to the CEIIC laboratory, where it is finally tested. "The result was a broadcast of 1.2 Terabit/s (32 channels at 40 Gbit/s), which is well above the maximum value so far known (16 channels at 10 Gbit / s) which was achieved in Korea" says Ernesto Ciaramella, Professor of Telecommunications at CEIIC of Sant'Anna School, a member of team that has followed the experiment step by step.

The communication systems that operate on fiber help to achieve transmissions at high capacity (several hundred Gigabit/s, on just one fiber). Such systems are currently in use worldwide and are the backbone of the global network of medium to long distance communication, and the basic infrastructure for the telephony network and the Internet. The use of such types of communication is not strictly limited to optical fibers. In some instances, it may be more convenient to make connections in free air (wireless) over limited distances.

Up to now the main drawbacks of this technology are linked to the air turbulences, weather conditions and to the difficulties to have a stable alignment of the terminals (automatically compensating for any effects of vibration). Generally, transmissions of this type are unstable over time and are limited to transmission capacity values that are far below systems of optical fibers.

The team say that this experiment demonstrates, for the first time, that is possible to establish a transparent and stable free space connection between two fiber trunks carrying ultra-wideband data traffic.

Posted to the site on 15th September 2008