The general trend towards growing demand for wireless data will soon require the exploitation of currently unused frequency bands of the electromagnetic spectrum. This will also include the visible light spectrum (400...800 Terahertz). VLC combines light and illumination with data communication. The technology is not new and some advancements in VLC research have already found their ways into communication standards (examples are IEEE 802.11 Li-Fi and IEEE 802.15.7).
The Internet of Things (IoT) connects small low-complex devices (for example, sensors, utilities, toys) to a wide-area network. Many of the IoT devices have small data rate requirements. A communication infrastructure that aims to connect a large amount of devices should be low-cost, non-intrusive, and available everywhere. VLC is an attractive choice and has many desirable properties (freedom of regulation simplicity).
Underwater Communication with VLC is an interesting alternative to radio frequency (RF) based wireless communication. VLC is relevant in environments in which radio waves cannot be used.
Among such environments, submarine and in-pool underwater communications are an interesting use case driving the development of underwater Internet of Things (IoT). In contrast to terrestrial wireless radio communications, communication in underwater wireless networks can be quite limited: The underwater channel exhibits severe attenuation to a radio signal. Infrared signals are more affected than signals of shorter wavelength (signals of higher frequency). Images taken underwater appear blue for that reason: Signals with blue light wavelengths penetrate a body of water more deeply than red or infrared optical signals.
Elliptic Works from Southampton, New York, USA, already offers a world-class VLC platform solution for consumer markets.
For submarine communication, unmanned vehicles monitoring and exploring the sea, such as Remotely Operated Vehicles (ROVs) and Autonomous Underwater Vehicles (AUVs), need to communicate data at larger distances and higher volumes. Wired solutions affect device mobility, and radio solutions cover only limited ranges. Most wireless underwater systems however exploit acoustic waves with very limited transmission rates (hundreds of bit per second).
Underwater Visible Light Communication (UVLC) allows for much higher rates (Megabits per second). Low-cost consumer UVLC systems operate typically with Light Emitting Diodes (LEDs). Laser diodes are used in other domains and require a reliable alignment towards the intended receiver.