Genome analysis improves optical testing

13 Feb 2008

Australian scientists have used genome analysis tools to create a technology that can identify the different sources of noise in optical signal transmission.

The new device, dubbed a multi-impairment monitor, is able to determine the precise cause of signal degradation during transmission over optical fibre. Such detailed knowledge of the reasons for signal loss and distortion will allow network operators to eliminate or compensate for these optical errors, which will be crucial to achieve faster data rates and longer link distances.

The scientists at NICTA, Australia's Information and Communications Technology (ICT) Research Centre of Excellence, claim that a device using the new technology will, for a few thousand dollars, do a job that today would require multiple types of test equipment costing more than $100,000. NICTA is spinning out a company to commercialize the technology, with a formal an announcement due within the month.

"The current tools available in the marketplace only count the errors in the data, telling the operator a problem exists but not what that problem is, where the problem is or what caused it," said Trevor Anderson, a principal researcher at NICTA who directs the Managing and Monitoring the Internet (MAMI) Project.

Anderson annd his team started by developing a way to represent an optical signal as a two-dimensional image. The image is formed by sampling the waveform, along with a delayed version of itself, to create a two-dimensional histogram of the signal.

"We thought that it would allow us to recognize the 'fingerprint' of the various kinds of optical noise that can interfere with the signal," Anderson explained. "But we didn't know how to analyse the image."

Fortunately, in the laboratory next door, a team of geneticists was analysing vast lengths of genetic code to find patterns of gene sequences that would indicate a tumour. "Dr Adam Kowalczyk looked at our problem, and laughed," said Anderson.

Dr Kowalczyk told Anderson: "This is easy – biology is so much more complex. We have to identify cancer subtypes using a handful of noisy examples to learn from rather than the thousands that are available to you."

So they tried out the genetic algorithms on the optical data, and found that they could be used to identify the distinct visual patterns created by the most common forms of noise and distortion in optical fibres.

"Our device can already identify the top four sources of noise and we expect to be able to do all six [common sources of impairments]," commented Anderson. "To the best of our knowledge the NICTA product is unique in that the same hardware is used for all impairments. New impairments simply require software upgrades."

NICTA anticipates that a standalone test and measurement unit will be ready for market in 12 months, and in the long term the scientists hope that the device can be made small and cheap enough to be embedded throughout long-haul networks. The group says it is working with almost 50 interested parties, who are mostly systems vendors from the metro and long-haul optical markets.

It's a second win for the NICTA team. Another device – an optical signal-to-noise ratio (OSNR) monitor – was recently licensed to an industry partner, US components maker Optium.