Breakthrough research could spur faster, cheaper internet

In a major breakthrough that would make the internet superfast and cheap, researchers have successfully increased the maximum power -- and therefore distance -- at which optical signals can be sent through optical fibres.

The advance has the potential to make the internet superfast by increasing data transmission rates for the fibre optic cables -- which serve as the backbone of the internet, cable, wireless and landline networks.

A long-standing roadblock to increasing data transmission rates in optical fibre has been that beyond a threshold power level, additional power surge irreparably distorts the information travelling in the fibre optic cable.

According to Nikola Alic from the Qualcomm Institute at University of California, San Diego, today's fibre optic systems were a little like quicksand.

With fibre optics, after a certain point, the more power one added to the signal, the more distortion set in, in effect preventing a longer reach.

Alic said their approach removed the power limit, which in turn extended how far signals could travel in optical fibre without needing a repeater.

The researchers were able to successfully decipher information, after it travelled a record-breaking 12,000 km through fibre optic cables with standard amplifiers and no repeaters.

The researchers found that by using a frequency comb data could be sent and received over long distanced without significant signal distortion.

Ordinarily, such signals were subject to crosstalk caused by a physical phenomenon known as the Kerr effect. The cross talk is greater at higher the power levels.

However, by manipulation of the signals to take into account the known physical properties of the Kerr effect before the data was even transmitted, the researchers could render the crosstalk reversible at the receiving end.

According to research scientist Bill Kuo, they were able to pre-empt the distortion effects that happened in the optical fibre. Kuo was responsible for developing the wide-band frequency comb used in the experiments.

With the method developed by the researchers, telcos would be able to boost their optical signals – and thus their data transmission rates – without the labour and expense of installing repeaters along their lines.

The study team of seven included five researchers from the University of California, San Diego, Department of Electrical and Computer Engineering and two researchers from the Qualcomm Institute, a division of the California Institute for Telecommunications and Information Technology that was named after the San Diego-based chipmaker, but operated jointly by UCSD and the University of California, Irvine.