Optical physics

Explore LiFi with the IOP

What is LiFi?

LiFi is a wireless technology connecting us to the internet which holds the key to solving challenges faced by 5G. LiFi is similar to WiFi, as both transmit data electromagnetically. However, WiFi uses radio waves whilst LiFi uses visible light to transmit high speed data that can reach multiple gigabits. LiFi is more reliable, virtually interference free and uniquely more secure than radio technology such as Wi-Fi or cellular.

The need for LiFi

Current WiFi technology already uses light travelling along fibre optic cables. Yet, the last few metres of wireless network connectivity into our home or office are still primarily delivered via radio waves.

As more and more devices connect to the internet, the space for radio frequencies is becoming over saturated. This is known as spectrum crunch. In the near future, there may not be enough wireless bandwidth to support growing consumer demand.

By using light for these last few metres of connectivity, LiFi opens up 1,000 times more bandwidth than using radio waves alone.

How does LiFi work?

A LiFi network uses the light from LED lamps to send data to a device, such as a laptop or tablet. The device has a receiver to pick up light signals and a transmitter to send light signals back to the lamp using infrared light.

The light from the LED lamps changes intensity billions of times a second, faster than the eye can see. This change in intensity becomes a digital signal which can carry information from the internet to a user and back again.

Multiple lights can be added to a single network, so that you can move around from light to light without losing your connection. You don't have to be directly under a lamp to use LiFi. The digital signal is also carried by light reflected off walls and other surfaces.

A LiFi network still needs a regular internet service provider to supply internet to a home or office via wires. LiFi can then be deployed within a home or office to provide a wireless internet connection to devices.

Applications for LiFi

Since light cannot penetrate through walls and doors, LiFi could be significantly more secure than other wireless technologies.

It could also be useful in places where Wi-Fi is a problem due to interference, such as hospitals and aircraft.

LiFi also has the potential to revolutionise the way we access data, providing 1000 times the band width of cellular and Wi-Fi combined. With an estimated 28.5 billion devices predicted to be connected to the internet by 2022, this could help to meet demand that would otherwise go unmet using Wi-Fi.

LiFi at the IOP

Visitors to our King’s Cross building can try out LiFi using the LiFi Demonstrator installed in our newly opened Accelerator Centre. This demonstrator has been built in partnership with pureLiFi, one our Business Award winners.

Further reading and viewing

Professor Harald Haas, University of Edinburgh, introduced LiFi to the public in a TED Global Talk in 2011 and coined the phrase LiFi. He is widely recognised as the ‘father of LiFi’. Professor Haas founded pureLiFi in 2012 along with his former postdoc Dr Mostafa Afagani.