Underwater wireless optical communication (UWOC) systems using the blue / green bands of the visible light spectrum stand out as an important solution in underwater applications that require high data communication rate such as remote sensing and navigation, real-time video transmission and imaging. The main factor that limits the data communication distance and determines the data rate in UWOC systems is the disruptive (absorption and scattering) effects of the underwater environment on optical waves. In this study, the signal to noise ratio (SNR) and channel capacity for UWOC systems are presented according to the divergence angle of the beam and the change in the aperture diameter of the receiver, which are the important parameters for UWOC systems. These examinations were repeated for pure sea water, clean ocean water, coastal ocean water and harbor water environments commonly used in the literature, and the obtained results were compared. With the presented results, the current limits for UWOC systems have been revealed and provide predictions about the applications that can be realized with UWOC systems for different environments.
