Experimental demonstration of high speed underwater visible light communications

We experimentally prove high-speed underwater optical wireless transmission over 2.5 m distance, using different bit rates and modulation schemes. The system uses two low-cost Light Emitting Diodes (LEDs) arrays as optical transmitter and an avalanche photodiode module as receiver. The measurements are taken using an outdoor water tank having 3.3 m diameter, where two waterproof boxes containing the transmitter and the receiver are fixed underwater at the inner borders. We test 6.25 Mbit/s with Manchester coding, 12.5 Mbit/s with NRZ 8b/10b coding and 58 Mbit/s with Discrete Multitone modulation. Bit Error Rate measurements are collected over several hours under typical summer sunlight illumination conditions. In all the experimental conditions we achieve error free transmission.