An investigation on large capacity transmission technologies for UWOC systems

Underwater wireless optical communication system (UWOC) is promising for underwater inspection and exploration owing to its advantages of sufficient bandwidth, high reliability, small-scale antennas, low cost and low latency. With the increasing demand for a high-speed communication system, three feasible schemes to achieve large-capacity underwater optical transmission system with tens Gbps transmission rate over relatively long transmission distance are investigated in this paper. They are Orthogonal Frequency Division Multiplexing (OFDM) with Laser diodes (LD), Wavelength division multiplexing (WDM) transmission and Orbital Angular Momentum (OAM) transmission technologies. OFDM is widely applied in the UWOC field due to its resistance to inter-symbol interference (ISI) and high spectral efficiency. Combined with other technologies, OFDM can significantly improve the performance of the system and capacity. WDM and OAM are two potential multiplexing technologies for UWOC, and they can combine to achieve large-scale transmission. (paper)