Recently, a variety of research are proceeding for underwater environment monitoring system and resource development. Underwater Communication infrastructures are required for underwater wireless sensor networks. Method of Underwater wireless communications are radio frequency communications, acoustic communications and optical communications. Underwater communication is severely limited when compared to communications in air because water is essentially opaque to electromagnetic radiation except in visible range. Acoustic systems are capable of long range communication, but offer limited data rates and significant latency due to the speed of sound in water.
On the other hand, optical wireless communication has been proposed as one of the best alternatives to meet the requirements of the underwater observation and subsea monitoring systems.
Therefore, visible light wireless communications is an alternative in underwater. Visible wavelength range have a lower absorption than electromagnetic wave at underwater. And it transmits big data such as photos and videos by using a wide bandwidth.
In this paper, we use the lens for connecting in parallel LED sending away the light. An interface between LED lighting communication system and Bluetooth module is presented to support the underwater-to-air communications. Error free image and text transmission at 3 m of water were achieved at bit rates of 230.4 kbps.