Effect of absorbing and non-diffracting particles in UWOC links

Underwater wireless optical communications (UWOCs) are subject to several phenomena related to light-matter interaction. Scattering due to particles and turbulences are factors that have been well studied in the last few years. However, for shallow-water links based on non-coherent sources as light emitting diodes, the impact of particles with higher dimensions that do not produce neither scattering nor diffraction has not been studied yet. In this work, a geometrical model to provide an estimation tool for shallow-water scenarios is presented. In this type of links, the emitter must be analysed as an extended source, since the effect of light-blocking particles cannot be correctly modelled using the traditional point-source approximation. The obtained results suggest that the effect of this kind of particles is large enough so as to take them into account when modelling UWOC links. The effect of these particles on the quality of the received optical signal depends on their size, concentration and other parameters such as the link's range and the endpoints' surfaces. Some interesting conclusions are extracted such as the existence of an optimal emission area.