Multidimensional underwater optical communication using coaxial polygonal vortex beam encoding

Increasing capacity and fidelity remains a primary challenge in underwater optical communication. An innovative and robust underwater optical communication system is proposed combining polygonal vortex beams with an improved Re-MobileViT recognition network. This system uses octal and quaternary coding schemes to encode and decode grayscale images, thereby enabling multidimensional encoding information transmission. The single-beam scheme achieves 8 distinguishable modes, while the coaxial combination scheme expands the codebook to 16 modes. An underwater turbid medium was simulated using milk to evaluate the transmission performance of polygonal vortex beam encoding. Images are transmitted by applying both orbital angular momentum and geometric dimensions for encoding and decoding, allowing the improved Re-MobileViT network to achieve high-precision recognition and improving the system’s robustness against interference. Experimental results demonstrate that the system maintains a transmission accuracy of over 99%, even under high turbidity.