Recent advances in underwater optical wireless communications

Optical wireless communications (OWC) are being considered for use under water because sea water exhibits a window of reduced absorption in the visible spectrum, particularly between 400-550nm. Recent technology has demonstrated the ability to support mid-range links (<200m) and at high bandwidths (<1Gbps) in clear oceans. The present paper outlines the governing transmission characteristics and reviews current experimental research in underwater OWC, highlighting the importance of the local chlorophyll concentration, particulate concentration and the resultant wavelength selection. Ideal wavelengths are found to be from 430nm, which represents a deep blue colour, to beyond 550nm in areas where the chlorophyll concentration is high.