March 17, 2009

Lasers may spread Internet to rural areas

Australian researchers say they are experimenting with lasers as a way to boost the reach of existing high-speed Internet service to large rural areas.

Ka Lun Lee and colleagues at the University of Melbourne say high-speed digital subscriber line or cable Internet service is too expensive to use in rural areas, since they require extensive networks of equipment and lines. Other technologies, such as satellite and fixed wireless, offer wider coverage but are often unreliable and expensive.

The researchers found gigabit passive optical networks provide the lowest cost at higher bitrates. But Lee said the reach of that technology into rural areas is limited by the loss in signal strength along the optical fiber, with each line only capable of radiating approximately 19 miles from a central office.

To boost that reach, Lee and his team use a device called a Raman amplifier. Installed in the central office of a network provider, the high-powered laser feeds the optical signal that carries information as it heads out over a fiber. That, said Lee, increases the power and reach of the signal by a factor of nearly 10.

The scientists will present their research Monday in San Diego during the Optical Fiber Communication Conference and Exposition/National Fiber Optic Engineers Conference.