Researchers Use Infrared to Boost Wi-Fi Speeds

Researchers at Eindhoven University of Technology in the Netherlands have figured out how to use infrared rays to dramatically increase the speed of Wi-Fi while eliminating network congestion.

Conceived by Joanne Oh as the subject of her doctoral work at the university, the system has a huge capacity of more than 40 gigabits per second (Gbps) per infrared ray and obviates the need to share because each wireless device gets its own ray of light, according to the university press release.

Described as simple and, in principle, cheap to set up, the system uses “light antennas” to transmit data.

The wireless data comes from a few central ‘light antennas’, for instance mounted on the ceiling, which are able to very precisely direct the rays of light supplied by an optical fiber. Since there are no moving parts, it is maintenance-free and needs no power: the antennas contain a pair of gratings that radiate light rays of different wavelengths at different angles (‘passive diffraction gratings’). Changing the light wavelengths also changes the direction of the ray of light.
Researchers say the technique is harmless because a “safe infrared wavelength is used that does not reach the vulnerable retina in your eye.”

A network of antennas tracks the location of every wireless device so when you walk out of the line of sight of one antenna another antenna takes over. And because devices are assigned different wavelengths, they do not have to share capacity and are immune to interference from a neighboring Wi-Fi network.

Whereas current Wi-Fi uses radio signals with a frequency of 2.5 or 5 gigahertz, Oh’s system uses infrared light with wavelengths of 1,500 nanometers and higher; this light has frequencies that are “thousands of times higher, some 200 terahertz, which makes the data capacity of the light rays much larger.”

Oh managed a speed of 42.8 Gbps over a distance of 2.5 meters, which compares with an average connection speed in the Netherlands that’s 2,000 times less (17.6 megabits per second, or Mbps). “Even if you have the very best Wi-Fi system available, you won’t get more than 300 Mbps in total, which is some hundred times less than the speed per ray of light achieved by the Eindhoven study,” the press release said.

So far the researchers have only used the light rays to download; uploads are still done using radio signals since in most applications much less capacity is needed for uploading.

Oh’s work is part of the wider BROWSE project project headed up by professor of broadband communication technology Ton Koonen, who expects it will be at least five years before the technology will be available to consumers.

The work of Oh and Koonen comes under the auspices of Eindhoven University of Technology’s Institute for Photonic Integration, one of the world’s leading research institutes for ‘photonics’, the use of light (photons) rather than electricity (electrons) to transmit data.