Researchers claim to double fiber-optic cable range minus repeaters

Mark Tyson at HEXUS.net, an independent technology news and reviews website based in the UK, is reporting that researchers at the University of California-San Diego now claim that thanks to their work, "a long-standing roadblock to increasing data transmission rates" in fiber-optic cabling has been removed.

The premise of the research is that, though fiber-optic cables used in the backbone of the Internet are often regarded as offering the ultimate in connection speeds, there are certain constraints. As engineers ramp up power levels, distortion limits the achievable speeds, as well as the cable lengths between repeaters, required to push more data though fiber cables aiming to span larger distances at faster rates.

Nikola Alic, a principal in the experimental effort, explains what the UC-San Diego research team has achieved, "Today's fiber-optic systems are a little like quicksand. With quicksand, the more you struggle, the faster you sink. With fiber-optics, after a certain point, the more power you add to the signal, the more distortion you get, in effect preventing a longer reach. Our approach removes this power limit, which in turn extends how far signals can travel in optical fiber without needing a repeater."

The application of wideband "frequency combs" to optical networking data transmission is reportedly the key innovation implemented by the research team. "Pre-empting the distortion effects that will happen in the optical fiber" makes cabling crosstalk predictable, and therefore reversible, at the receiving end, adds Alic.

Using the new technique, data transmissions were sent and successfully decoded after passing though a record-breaking 12,000 kilometres (nearly 7,500 miles) of fiber-optic cable. Further, only standard amplifiers were used for the experiment, and no repeaters deployed. Normally, expensive repeater equipment must be stationed every 100 kilometres (60 miles) along a cabling route to eliminate signal corruption by noise, notes the report.

More technical details about the experiment are available in the journal Science, and on the UC San Diego Jacobs School of Engineering Blog.