Li-Fi

Imagine a world where every one of the billions of lightbulbs in use today is a wireless hotspot delivering connectivity at speeds that can only be dreamed of with Wi-Fi. That's the goal of the man who invented such a technology, and this week Li-Fi took a step out of the domain of science fiction and into the realm of the real when it was shown to deliver speeds 100 times faster than current Wi-Fi technology in actual tests. Li-Fi refers to visible light communications (VLC) technology, which delivers high-speed, bidirectional, networked mobile communications in a manner similar to Wi-Fi. It promises huge speed advantages, as well as more-secure communications and reduced device interference.

How does Li-Fi Work?


 

 When a constant current is applied to an LED [light-emitting-diode] lightbulb, a constant stream of photons are emitted from the bulb which is observed as visible light. If the current is varied slowly, the output intensity of the light dims up and down. Because LED bulbs are semiconductor devices, the current, and hence the optical output, can be modulated at extremely high speeds which can be detected by a photodetector device and converted back to electrical current. The intensity modulation is imperceptible to the human eye, and thus communication is just as seamless as RF [radio frequency technology]. Using this technique, high-speed information can be transmitted from an LED lightbulb.