IT and Society: Germany sets a new record for the rate of data transfer – 26 terabits per second

Researchers at Karlsruhe Institute of Technology in Germany have set a new record for the rate of data transfer. They succeeded in sending 26 terabits – the equivalent of 700 DVDs – down an optical fibre in one second using a single laser. The trick is to use what is known as a "fast Fourier transform" to unpick more than 300 separate colours of light in a laser beam, each encoded with its own string of information. In the current experiment, the team sent their signals down 50km of optical fibre.

Earlier physicists too succeeded in transferring data using the laser and even at great speeds (about 100 terabits per second). The problem was they didn't have just one laser, they had hundreds of lasers which served as transmitters (Orthogonal frequency division multiplexing). Each of them was working with its own color, and they all mixed different colors through the fiber together. However scientists claim that “they fill racks and consume several kilowatts of power”.

Professor Wolfgang Freude and his colleagues from different countries have worked out how to replicate similar speeds using a single laser with extremely short pulses. Once sent into an optical fibre, the colours can add or subtract, mixing together and creating about 325 colours, each of which can be encoded with its own data stream.

The Fourier transform extracts the colours from an input beam on the basis of when the different elements of the beam arrive. Professor Freude's team does this optically by splitting the incoming beam into different paths that arrive at different times and recombining them on a detector.

Researchers from Karlsruhe are expecting integration of the technology in future micro chips – which means it would be ripe for commercial exploitation. Professor Freude is convinced that it will be in demand as ever-higher data rates become desirable.