26 Jun 2012

Researchers transmit data at 2.56Tb per second

A multi-national team led by US-based University of Southern California has developed a system of transmitting data using twisted beams of light at ultra-high speeds – up to 2.56 terabits per second.

Broadband cable supports up to about 30 megabits per second, so the twisted-light system transmits more than 85,000 times more data per second.

The work could be used to build high-speed satellite communication links, short free-space terrestrial links, or potentially be adapted for use in the fibre-optic cables that are used by some Internet service providers.

"You're able to do things with light that you can't do with electricity," said Alan Willner, electrical engineering professor at the USC Viterbi School of Engineering. "That's the beauty of light; it's a bunch of photons that can be manipulated in many different ways at very high speed."

Willner and his colleagues used beam-twisting "phase holograms" to manipulate eight beams of light so that each one twisted in a DNA-like helical shape as it propagated in free space.

Each of the beams had its own individual twist and can be encoded with "1" and "0" data bits, making each an independent data stream – much like separate channels on your radio.

Their demonstration transmitted the data over open space in a lab, attempting to simulate the sort of communications that might occur between satellites in space.

Among the next steps for the research field will be to advance how it could be adapted for use in fiber optics, like those frequently used to transmit data over the Internet.

"We didn't invent the twisting of light, but we took the concept and ramped it up to a terabit-per-second," Willner said.

• The DARPA-sponsored research is published in Nature Photonics

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