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Wi-Fi at the Speed of Light

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Experimental system transfers data at one gigabit per second. Infrared laser (black device on right) transmits the data.

Penn State University

A wireless network that uses reflected infrared light instead of radio waves has transmitted data through the air at a speed of one gigabit per second—six to 14 times faster than the fastest Wi-Fi network.

Such optical networks could provide faster, more secure communications and would be especially suitable for use in hospitals, aircraft, and factories, where radio-frequency transmission can interfere with navigation equipment, medical devices, or control systems.

Another possible application is wireless networking for home theaters; a system that transmits data at 1.6 gigabits per second could broadcast two separate high-definition TV channels across a room, a capacity that exceeds the bandwidth of any existing radio system.

Penn State graduate student Jarir Fadlullah and Mohsen Kavehrad, professor of electrical engineering and director of the university's Center for Information and Communications Technology Research, built and tested the experimental system.

Their setup sent data across a room by modulating a beam of infrared light that was focused on the ceiling and picking up the reflections using a specially modified photodetector. The pair says that their measurements show the system could support data rates "well beyond" the one gigabit per second they are currently claiming.

"This probably will be the next generation wireless communications technology," says Zhengyuan Daniel Xu, professor of electrical engineering at the University of California, Riverside. Xu is also the director of the UC-Light Center, a consortium of researchers working on wireless optical communications at different UC campuses. "Light will give you higher data rates than radio frequencies, and RF already has a very congested spectrum."

From Technology Review
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