AmphiLight: direct air-water communication with laser light

Air-water communication is fundamental for efficient underwater operations, such as environmental monitoring, surveying, or coordinating of heterogeneous aerial and underwater systems. Existing wireless techniques mostly focus on a single physical medium and fall short in achieving high-bandwidth bidirectional communication across the air-water interface. We propose a bidirectional, direct air-water wireless communication link based on laser light, capable of (1) adapting to water dynamics with ultrasonic sensing and (2) steering within a full 3D hemisphere using only a MEMS mirror and passive optical elements. In real-world experiments, our system achieves static throughputs up to 5.04 Mbps, zero-BER transmission ranges up to 6.1 m in strong ambient light conditions, and connection time improvements between 47.1% and 29.5% during wave dynamics.