Underwater optical wireless communication with subcarrier intensity modulation: an experimental demonstration

This paper presents an experimental study of an underwater optical wireless communications system (UOWC). The potential of UOWC and how it can operate alongside acoustic based communications in a hybrid system is outlined. The channel characteristics, in terms of the inherent optical properties of water, are described and the impact on data transmission assessed. We present data transmission with a blue laser diode using both on-off keying (OOK) and subcarrier intensity modulation (SIM). These modulation schemes are evaluated in both still and turbulent water, demonstrating the inherent resilience to turbulence of SIM as well as the impact of turbulence on signal transmission. We show a maximum data rate in the range of Gbps, showing the potential for high speed underwater communications links using UOWC.