Optical analysis

Australian scientists have developed a system that can identify the causes of noise in the optical cables that form the backbone of the internet.


The system that the engineers at NICTA, Australia’s Information and Communications Technology (ICT) Research Centre of Excellence, have invented, will, for a few thousand dollars, do a job that today would cost over $100,000 and would require multiple types of test equipment.


It will allow phone companies to confidently increase the speed ratings on long haul optical fibres from 10 gigabits per second to 40 gigabits per second or more without losing data in the noise in line.


The six most common sources of signal impairments in fibre optical cable are caused by optical amplifier noise, too much dispersion as the laser beam travels down the fibre, a fibre that’s not quite symmetric – leading to more dispersion of the signal, power levels that are too high, interference from adjacent channels and unwanted reflections.


‘The current tools available in the market 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 NICTA principal researcher Trevor Anderson, who is based at NICTA’s Victoria Research Laboratory and directs the Managing and Monitoring the Internet (MAMI) Project.


‘Our device can already identify the top four sources of noise and we expect to be able to do all six,’ he said.


Anderson anticipates the device will be ready for market in 12 months. In the long-term, the researchers hope that it will be small enough and cheap enough to be embedded throughout long haul networks.


Patents have been lodged for the technology and telecommunications companies are said to be lining up to discuss the potential.


This is a second major win for the NICTA team. Another device – an optical signal-to-noise ratio (OSNR) monitor – has already been licensed to an industry partner, Optium. It can distinguish and measure the impairment caused by optical amplifier noise, improving the ability to manage the network.


‘We expect the information provided by the monitor could save telecommunications carriers the time and expense that is currently required to deploy a truck and technicians to fix a problem on a network and to provision new services,’ Anderson said.