Saudi scientists create 'fastest li-fi luminaire in the world'

Scientists in Saudi Arabia claim to have created the fastest li-fi luminaire in the world.

The experts at the King Abdullah University of Science and Technology (KAUST) have apparently created a device that is able to transmit data 20 times faster than any previously existing li-fi luminaire.

Standard li-fi devices already offer a service that is 100 times faster than average wi-fi speeds.

LED wi-fi devices traditionally work by combining blue light with phosphors, which turns part of the radiation produced into red and green light, resulting in the white light required for any luminaire.

‘Visible light communication generated in this way is generally limited to about one hundred million bits per second,’ Boon Ooi, professor of engineering at KAUST told Daniel Oberhaus of Motherboard magazine.

There is a limit on the amount of data that can be transferred in such a set-up becuase the process of generating white light is much slower than the rate at which an LED light can be turned on and off.

As well as a considerably improvement in data transmission times, the light emitted by the new luminaire was comparable to other LED lights and was more energy efficient.

The amount of time it takes a luminaire to turn on and off is key, as it is through the process of switching off and on that the LED communicates.

A li-fi luminaire switches off and turns back on again quicker than the naked eye can see and during this process communicates with a receiver. The faster this happens the greater the bandwidth available to users.

Phosphors, which emit light when exposed to radiation, are generally made of photoluminescent material, which has a very long lifetime, thus acting to limit bandwidth.

The researchers found that the addition of nanocrystalline decreased the photoluminescent material’s lifespan from microseconds down to nanoseconds.

This allows bandwidths of nearly 500 megahertz and data transmission rates of up to two billion bits per second (2 Gbps), a 20-fold increase over other VLC technologies operating at around 100 million bits (100 Mbps).

When illuminated by a blue laser light, the nanocrystals emit some green light, while the nitride emits red light, creating the necessary white light.

As well as a considerable improvement in data transmission times, the light emitted by the new luminaire was comparable to other LED lights and was more energy efficient.

  • Innovations in li-fi will be demonstrated at the  LuxLive 2016 exhibition in London on Wednesday 23 November and Thursday 24 November 2016. A special IoT Arena will explore developments in connected lighting and its role in the Internet of Things. Click here to register. 


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