An Eindhoven University of Technology (TU/e) scholar has built a wireless network system that can transfer data at speeds of 42.8 Gbit/s using infrared light.
This breakthrough also earned TU/e researcher Joanne Oh her PhD degree with the ‘cum laude’ distinction.
According to Oh, the system is simple and cheap to set up. The wireless data comes from a few central ‘light antennas’ mounted on the ceiling, which are able to very precisely direct the rays of light supplied by an optical fiber.
Its fixed nature allows it to be maintenance- and power-free: 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. Since a safe infrared wavelength is used that does not reach the vulnerable retina in your eye, this technique is harmless.
The new system does away with interference from a neighboring wi-fi network: If you walk around as a user and your smartphone or tablet moves out of the light antenna’s line of sight, then another light antenna takes over.
The network tracks the precise location of every wireless device using its radio signal transmitted in the return direction. It is a simple matter to add devices: they are assigned different wavelengths by the same light antenna and so do not have to share capacity.
The system further trounces current wi-fi radio signals in matters of frequencies used. As opposed to the wi-fi frequency of 2.5 or 5 gigahertz, TU/e’s system uses infrared light with wavelengths of 1500 nanometers and higher; this light has frequencies that are thousands of times higher, say somewhere around 200 terahertz, which makes the data capacity of the light rays much larger.
Oh even managed a speed of 42.8 Gbit/s over a distance of 2.5 meters. For comparison, the average connection speed in the Netherlands is two thousand times less (17.6 Mbit/s). Even if you have the very best wi-fi system available, you won’t get more than 300 Mbit/s in total, which is some hundred times less than the speed per ray of light achieved by the Eindhoven study.
The Eindhoven system has so far used the light rays only to download; uploads are still done using radio signals since in most applications much less capacity is needed for uploading.
Image, excerpts and source: Shutter_M/Shutterstock.com, Eindhoven University of Technology