Performance evaluation of an 80 Gbps dual-polarization orbital-angular-momentum-based underwater optical wireless communication system

Abstract

In this paper, a new underwater optical wireless communication (UOWC) system is proposed. It integrates dual-polarization (DP) states with orbital angular momentum (OAM) beams. By leveraging the inherent orthogonality of different OAM modes, the system achieves enhanced signal quality and increased transmission capacity. Each polarization state carries data of four OAM beams, with each capable of carrying 10 Gbps of information. Additionally, a single laser diode (LD) source operating at 532 nm is employed. To evaluate the performance of the proposed system, the effects of attenuation across various water types are considered. Propagation range, bit error rate (BER), and eye diagrams are utilized as comprehensive performance metrics. The obtained results indicate that, below the error correction threshold (3.8×10−3), our proposed UOWC system achieves impressive underwater transmission ranges. Specifically, we observe a longer range of 44 m for pure sea (PS) water that exhibits the lower attenuation, which is decreased to 26.5 m for clear ocean (CL) and 15.5 m for coastal ocean (CS). Furthermore, it decreased reaching shorter ranges of 8 m for harbor I (HI) and 4.45 m for harbor II (HII), which have the highest attenuation.