As you know, radio waves propagate poorly under water, which greatly complicates communication between divers and submarines when sending information to the surface.
In 2018, King Abdullah University of Science and Technology (KAUST) PhD student Abdullah Al-Khalafi and his research advisor, Bassem Shihada, developed an underwater wireless optical communications (UMOC) system that allows HD video to be transmitted in an aquatic environment. Based on this technology, a new system was created, called Aqua-Fi.
How it works. For example, a scuba diver begins to transfer photo or video information from a smartphone placed in a protective case. Initially, it is broadcast in the form of radio waves to a small device located in the immediate vicinity of it on cylinders with air.
The microcomputer of this device then converts the information into a series of light pulses. The binary-coded pulses are then sent to the receiver by a built-in 520nm laser or an array of green LEDs.
The difference is that LEDs transmit information over short distances using little power, while a laser can relay them further, but at the same time consuming significantly more power.
Upon reaching the surface, the coded pulses are sent to a photodetector installed at the bottom of the vessel, after which they are converted into familiar photos or videos using a connected computer. Then the files can be uploaded to the Internet via satellite.
Previously, Aqua-Fi technology was only tested for sharing video files between two PCs placed in a static aquatic environment at a distance of about 5 meters. However, in order to use the system in a daily environment, a number of problems remain to be solved, for example, adapting it to the scattering effect of light from moving water, which may require a spherical receiver capable of receiving light pulses from all directions.