Terabit-class data pipes movies in an instant

Advanced maths brought to bear on fibre-optic speed problem

When it comes to internet speeds, we've long-since consigned the humble kilobit-class connection to the dustbin, so a mathematics-based breakthrough has us wondering if megabit- and even gigabit-level connections will one day sound as quaintly archaic.

Researchers at Japan's Tohoku University have tweaked existing protocols to enable standard fibre-optic cables to carry data at hundreds of terabits per second [Subscription link]. At that speed, full movies could be downloaded almost instantaneously in their hundreds.

QAM made stable

At the heart of the development is a technique already used in some digital TV tuners and wireless data connections called quadrature amplitude modulation (QAM). One glance at the Wikipedia explanation shows that it's no easy science, but the basics of QAM in this scenario require a stable wavelength for data transmission.

As the radio spectrum provides this, QAM-based methods work fine for some wireless protocols, however the nature of the optical spectrum means this has not been the case for fibre-optic cables ... until now.

The university team has solved the stability problem using a special laser that makes it feasible to pipe data down a glass fibre using the QAM method at blistering speeds. Although we shouldn't expect to be choosing from internet connections rated in Tbit/s anytime soon, the development could one day make us look back on ADSL as fondly as we now do our 56K modems.

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