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Li-Fi: the new Wi-Fi

Luciom and Leti, a CEA Tech institute, have developed a new high-data-rate bidirectional Li-Fi modem as a radio-wave free alternative to Wi-Fi that won't saturate networks.

Published on 15 July 2015

Li-Fi technology, around since the early 2000s, uses the same LEDs that illuminate a room to transmit data. Here’s how it works: bulbs are switched on and off at ultrahigh speeds, converting digital information into optical signals. Until recently, Li-Fi could only be used for low-speed applications; plus, data could only be transmitted in one direction, from LED to user.

Now Leti and Luciom researchers have combined their mastery of optics and digital communications to develop a new Li-Fi modem better able to “modulate” LED light. Luciom was tasked with improving the transceivers that convert the electrical and optical signals. Additional research was then completed to improve the initial prototype. The enhanced prototype has a photodiode that receives optical signals of between 1 MHz and 10 MHz—making them invisible to the human eye—and converts them into digital signals, achieving speeds of up to 20 Mb/s. The modem connects to a computer’s USB port and can also emit an infrared signal that is received by the room’s LEDs.  

The system is a more efficient alternative to Wi-Fi, offering Wi-Fi-like speeds with the added benefits of enhanced security and resistance to electromagnetic interference. Li-Fi will prove especially useful in places like nuclear facilities, aircraft, hospitals, and daycare centers, where RF waves would be harmful or disruptive.

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