Italian and Japanese team sets new world record for free-space optical transmission
September 16, 2008--A new world record for free-space, laser-based wireless optical transmission was achieved by a team from the Centre of Excellence for Information Engineering and Communication (CEIIC) of the Sant'Anna School of Advanced Studies (Pisa, Italy) in collaboration with the National Institute of Information and Communications Technology (NICT) and Waseda University in Japan: 1.28 Terabit/s (or 1280 Gigabit/s) in a free air link between two transceivers spaced 210 m apart.
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 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.
In some instances, it may be more convenient to make connections in free air (wireless) over limited distances. For example, this technology can be used for disaster recovery (a quick restoration of a buried line that is no longer available; for example, it was used in New York after 9/11 to bridge links between skyscrapers that had been cut off the network and adjacent skyscrapers that were still connected). It may also be useful to avoid the practical problems related to laying fiber (for example when cable is laid across busy roads thus holding up the traffic) or to achieve flexibility when connecting the antennas of a cellular network.
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