Underwater Solar Cell Arrays Prove Capable of 150Mbps Optical Communication Between Devices

A team of researchers at Zhejiang University has come up with an interesting way for underwater drones, devices, divers, and deep-down submarines to communicate quickly and without physical contact: solar cells.

"There is a critical need for efficient underwater communication to meet the increasing demands of underwater data exchange in worldwide ocean protection activities," says research lead Jing Xu of his team's work. "This type of system could even allow data exchange and power generation with one device."

The system in question: An array built from commercially-available solar cells, which offers the ability to quickly detect light — and over a considerably larger surface area than the photodiodes typically used. As a result, it's possible to use them as the receiving end of a wireless optical transmission without the alignment issues that would normally prevent successful communication.

"Until now, achieving high-speed links using off-the-shelf silicon solar cells has required complex modulation schemes and algorithms, which need intense computing resources that use extra power and create a high processing latency," Xu explains of the reason the approach, which uses technology traditionally optimized for power generation rather than communication, hasn't seen success in the past.

"Using modeling and simulation of connected solar cells, we optimized the peripheral circuit, which significantly improved the performance of our solar cell-based detector."

The prototype 3×3 solar array, deployed into a water tank that used mirrors to create an optical signal path of 35 meters, proved the concept: The ability to transmit at 150Mbps entirely underwater, while also being able to harvest energy from both the transmission and ambient light.

"Because solar cells are mass produced, the proposed scheme is quite cost effective," Xu concludes. "Beyond the underwater world, this type of detector could also be used in visible light communication, a type of wireless communication that uses visible light from LEDs and other sources to transmit data across distances."

The team's work has been published in the journal Optics Letters under closed-access terms.