Researchers from the Karlsruhe Institute of Technology, Germany used 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.
At the faster end of the laser telecommunications technology is the “orthogonal frequency division multiplexing”, which uses a number of lasers to encode different strings of data on different colours of light, all sent through the fibre together.
At the receiving end, another set of laser oscillators can be used to pick up these light signals, reversing the process.
Professor Wolfgang Freude, a co-author of the current paper on the single laser technique, says about the mult-plexing approach that “already a 100 terabits per second experiment has been demonstrated.”
“The problem was they had something like 500 lasers, which is an incredibly expensive thing. If you can imagine 500 lasers, they fill racks and consume tens of kilowatts of power.”
Professor Freude and his colleagues have instead worked out how to create comparable data rates using just one laser with exceedingly short pulses.
Within these pulses are a number of discrete colours of light in what is known as a “frequency comb”.
When these pulses are sent into an optical fibre, the different colours can add or subtract, mixing together and creating about 350 different colours in total, each of which can be encoded with its own data stream.
Last year, Professor Freude and his collaborators first demonstrated how to use all of these colours to transmit over 10 terabits per second.
They see the development of the single laser technology as having the greatest commercial potential for cost effective data transfer in the near future.
And yes you guessed it. Professor Wolfgang Freude is a European regional finalist in this months ‘coolest name’ for an academic competition.