woman using phone underwater

Laser system provides wireless internet underwater

Image credit: Dreamstime

A system which uses beams of light to broadcast wireless internet underwater could be used to allow divers to instantly send live footage to the surface.

Water rapidly absorbs radio waves, limiting normal wireless communications like mobile networks beyond the shallows.

However, a team from King Abdullah University Of Science & Technology (KAUST) has developed a system called Aqua-Fi, which is capable of transferring data through the visible light spectrum using LEDs or lasers.

While LEDs provide a low-energy option for short-distance communication, lasers can carry data further and require more power.

The Aqua-Fi prototype used green LEDs or a 520nm laser to send data from a  simple computer to a light detector connected to another computer. The first computer digitises photos and videos and sends these corresponding signals as flashing beams of light. The light detector captures this signal, and the receiving computer converts it back into the original footage.

The researchers tested the system by simultaneously uploading and downloading multimedia between two computers set a few meters apart in static water. They recorded a maximum data transfer speed of 2.11MBps and an average delay of 1.00ms for a round trip.

“This is the first time anyone has used the internet underwater completely wirelessly,” said first author Basem Shihada.

In a fully implemented system, Aqua-Fi would use radio waves to send data from a diver’s smartphone to a “gateway” device attached to their gear. This gateway is then used transmit data via a light beam to a computer at the surface connected to the internet via satellite.

Aqua-Fi will not be available until the researchers overcome several obstacles: “We hope to improve the link quality and the transmission range with faster electronic components,” Shihada said.

The light beam must also remain perfectly aligned with the receiver in moving waters, and the team is considering a spherical receiver that can capture light from all angles.

“We have created a relatively cheap and flexible way to connect underwater environments to the global internet,” he said. “We hope that one day, Aqua-Fi will be as widely used underwater as WiFi is above water.”

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