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"Twisted" OAM Beams Carry 2.5 Terabits Per Second
MrSeb writes "American and Israeli researchers have used twisted, vortex beams to transmit data at 2.5 terabits per second. As far as I can discern, this is the fastest wireless network ever created — by some margin. These twisted signals use orbital angular momentum (OAM) to cram much more data into a single stream, without using more spectrum. In current state-of-the-art transmission protocols (WiFi, LTE, COFDM), we only modulate the spin angular momentum (SAM) of radio waves, not the OAM. If you picture the Earth, SAM is our planet spinning on its axis, while OAM is our movement around the Sun. Basically, the breakthrough here is that researchers have created a wireless network protocol that uses both OAM and SAM. In this case, Alan Willner and fellow researchers from the University of Southern California, NASA's Jet Propulsion Laboratory, and Tel Aviv University, twisted together eight ~300Gbps visible light data streams using OAM. For the networking nerds, Willner's OAM link has a spectral efficiency of 95.7 bits per hertz; LTE maxes out at 16.32 bits/Hz; 802.11n is 2.4 bits/Hz. Digital TV (DVB-T) is just 0.55 bits/Hz. In short, this might just be exactly what our congested wireless spectrum needs."
This is very cool, but the current super high bandwidth demonstration is being done with optical light over very short (1 meter) distances.
The article did point to an article from a couple months ago about the first ever OAM transmission; which was done with radio waves. But the antennas used look very directional and there was no mention of bandwidth.
Optical might be useful to further increase the speed of fibers, and highly directional radio might help for satellite broadcast or to compete with microwave relay towers. But requiring highly directional antennas, on both ends, isn't good for mobile wireless.
Hopefully we'll see another story soon where someone figures out how to detect and transmit OAM encoded radio waves from non-directional antennas.
I wouldn't get too excited.
Network technology has been steadily advancing, yet in the U.S. Internet access speeds and costs have remained stagnant.
When Fascism comes to America, it will call itself Anti-Fascism, and tell you to give up your guns.