Web surfing using light: LiFi coming

Light is already used to transmit data across fibre optic networks at high speed. Photo / Thinkstock

Researchers at Oxford University are developing a wireless networking technology that uses light to beam information through the air at more than 100 gigabits per second.

The technology could eventually provide a much faster alternative to WiFi, which currently tops out at about 7 gigabits per second (Gbps).

Light is already used to transmit data across fibre optic networks at high speed. However, transmitting information by beaming light through the air is more difficult, because there is no "light tunnel" to guide the signal.

The researchers, led by photonics engineer Dominic O'Brien, have developed a system that uses a base station installed on the ceiling of a room to send and receive light signals from a computer.

The transmitter and receiver are both fitted with holographic beam steering technology, which uses an array of liquid crystals to create a "programmable diffraction grating" that reflects the light in the desired direction.

The technology works at distances of up to 3m but the system requires a direct line of sight and for now, the computer must be in a fixed position.

The speed of the system also depends on the field of view of the receiver; if the base station has a 60-degree field it can use six wavelengths, while a 36-degree field only supports three wavelengths.

The next step, according to O'Brien, will be to develop a tracking system so that a user can place a laptop at a random spot on a table and have the system find it and create a link.

O'Brien's work is part of a larger effort to develop light-based wireless communications (known as LiFi), which uses the light that is already illuminating a room to send data signals.

Telegraph Group Ltd