Researchers at Eindhoven University of Technology have devised a Wi-Fi network with remarkable speed and huge capacity. The network, based on harmless infrared rays, is simple, maintenance-free and needs no power.
Current Wi-Fi uses radio signals with a frequency of 2.5 or 5 gigahertz. The infrared light-based system has frequencies that are thousands of times higher—200 terahertz—making the data capacity of the light rays much larger. The best Wi-Fi system available provides about 300 Mbit/s (megabits per second) in total, one hundred times less than the speed per ray of light achieved by the Eindhoven study.
In the Eindhoven system, wireless data comes from a few central “light antennas” which precisely direct light rays supplied by an optical fiber. The antennas contain a pair of gratings—passive diffraction gratings—that radiate light rays of different wavelengths at different angles. Changing the light wavelengths also changes the direction of the ray of light. Since a safe infrared wavelength is used that does not reach the vulnerable retina in your eye, this technique is harmless.
This system provides additional advantages. If a user moves out of a light antenna’s line of sight, another antenna will take over. The network tracks the precise location of every wireless device using its radio signal transmitted in the return direction. New devices operate on different wavelengths and do not have to share capacity. Moreover, there is no longer any interference from a neighboring Wi-Fi network.
Lead researcher Joanne Oh focused on data transmission. Related research at Eindhoven addresses different aspects of the network, including the central fiber optic network and device tracking technologies.