Highly robust underwater wireless optical communication system with optical background rejection and adaptive...

The concurrent operation of underwater wireless optical communication (UWOC) and artificial illumination represents a crucial functional requirement for underwater platforms. Nevertheless, intense background illumination significantly interferes with the performance of optical communication, leading to a reduction in the signal-to-noise ratio (SNR), an increase in bit-error rates (BER), and ultimately resulting in communication failure. We demonstrate a highly robust UWOC system that achieves an over 30 dB system-level equivalent tolerance to background illumination, including over 20 dB optical rejection and over 10 dB electrical-domain equivalent suppression. This system is enabled by a synergistic optical-electrical architecture comprising spectral avoidance, 5-ns gated sampling centered on the line-of-sight peak, and a real-time FPGA-implemented sliding-window adaptive decision threshold (ADTSW) algorithm. Under 300 W continuous illumination, we successfully achieved a 33 m underwater optical communication link with 20 Mbps in pool water and uninterrupted high-definition video streaming transmission between mobile platforms, in the South China Sea at the 17 m communication link with 3.125 Mbps. The proposed UWOC system offers a reliable solution for underwater data links in strong illumination environments.