MUNICH -- A new world record for the amount of data that can be pumped over a single strand of fiber -- 7.04 Terabits a second -- is being claimed by Optisphere Networks Inc., the newly created optical networking division of Siemens AG (Frankfurt: SIE).

A paper describing how this was achieved is scheduled to be presented here at the European Conference on Optical Communications (ECOC) next Thursday.

7.04 Tbit/s more than doubles the previous record of 3.2 Tbit/s, according to Jorg-Peter Elbers, director, optical networks, in Siemens's advanced transport systems network architecture business unit.

The record was set in Siemens's labs a couple of weeks ago and is a demonstration of how far technology can be pushed, Elbers says. It's not supposed to illustrate a practical way of running a high-performance transmission system, he adds.

Here's how it was set up. First, some DWDM systems were set up to generate 88 wavelengths of light in each direction over a 50-kilometer length of fiber. That's 44 wavelengths in the so-called C band and another 44 channels in the L band, generated at both ends.

The wavelengths carrying traffic in one direction were spaced 100 GHz apart and were interleaved with the wavelengths carrying traffic in the opposite direction. As a result, the overall spacing was 50 GHz.

Each wavelength carried 40 Gbit/s. This was achieved using transmission systems from Corning Inc. (NYSE: GLW). These systems use electrical time-division multiplexing to combine four 10-Gbit/s streams of data into a single wavelength.

The bottom line is 176 wavelengths each carrying 40 Gbit/s, which equates to 7.04 Tbit/s.

-- Peter Heywood, international editor, Light Reading http://www.lightreading.com