Experimental study of light wave propagation for underwater Optical Wireless Communication (UOWC)

Abstract

Underwater Optical Wireless Communication (UOWC) is identified as a promising technology because it offers higher bandwidth than acoustics and radio frequency techniques. This paper investigates the performance of light wave propagation for UOWC through experimental approach. An experimental set-up is developed consists of a transmitter, receiver and a glass chamber to emulate the water channel. Three types of water including clear, sea and cloudy are used to investigate their interaction with the light emitted by light emitting diode (LED) and laser diode. The geometrical loss (GL) analysis shows the white LED suffered a severe GL (GL<<1) as the transmission link increases due to the wide viewing angle while green and yellow LED obtained an equal GL due to the same size of viewing angle. However, red laser does not experience any GL. Therefore, the received power by red laser is 35% higher than by green LED. The analysis deduces that the estimated attenuation coefficient c had an increase of 15% and 55% for green LED and red laser respectively when the UOWC medium changed from clear water to sea water. This study contributes to identify the potential and limitations of different parameter design in order to optimize UOWC performance.