Imagine working in an office where turning on the lights also meant turning on internet access; an office where you could go online and do what you do up to 100 times faster than you currently do with wi-fi. It may sound the stuff of futuristic films, but it is now reality. The world of li-fi has arrived and should be ready for consumers within the next couple of years. Li-Fi is a technology that transmits computer data using the visible light spectrum rather than radio waves. It was first demonstrated at a TED exhibition conducted by Professor Harold Haas at Edinburgh University in 2011. Since that early demonstration showing an LED light transmitting a video, the technology has undergone further development that now makes it incredibly fast and comparatively reliable. The latest li-fi technology was recently tested by an Estonian start-up known as Velmenni. The company used a light bulb fitted with li-fi to transmit data as fast as 1 GB per second. According to Velmenni, speeds of up to 224 GB per second are theoretically possible based on their laboratory testing. Velmenni chief executive Deepak Solanki was quoted by the BBC as saying he hopes the technology will be ready for consumers “within three or four years”.

Making Light-based Technology Better

The idea of transmitting data via light is nothing new in principle. Since the earliest days of infra-red remote controls, we have been using light beams as a means of sending information from one point to the next. Indeed, the whole idea of optical fibre and data communications is based in the reality that light travels faster than electrical impulses. Some of our fastest internet connections today are based on this understanding. In terms of wireless communications, it is no different. The radio waves on which we depend for wi-fi signals are incredibly slow when you compare them to how fast light travels. The developers of li-fi know this and are taking advantage of it. But there's something else they know: the spectrum of visible light scientists have to work with is 10,000 times greater than the volume of radio waves we currently use for wi-fi. This means that, when li-fi is finally ready for commercial and individual use, it will be a long time before we run out of usable space in the light spectrum. There are drawbacks to the technology that Velmenni and others acknowledge. First and foremost, it cannot realistically be used outside because natural sunlight interferes with data transfer. Second, light does not pass through walls or floors. Therefore, it is only feasible in isolated spaces. But those two issues notwithstanding, it could replace traditional wi-fi in office environments, restaurants and cafés, and other public spaces where wi-fi is currently used for public internet access. The age of li-fi is here. It is only a matter of time before transmitting data with a receiver and a few LED light bulbs will be the norm. Source:   BBC – http://www.bbc.com/news/technology-34942685