Underwater wireless optical communication using a directly modulated semiconductor laser

Compared with the well-established techniques for underwater acoustic communication, underwater wireless optical communication provides much higher transmission bandwidth and can be an interesting alternative in short range underwater applications. We experimentally investigated the feasibility of using a directly modulated semiconductor laser as the transmitter in an underwater wireless optical communication (WOC) system. We transmitted pseudo-random binary sequence signals with four different bit rates (5Mbps, 10 Mbps, 15Mbps, 20 Mbps) through three different channels, with eye diagram being plotted and the bit error rate being calculated. No obvious signal distortion induced by water was observed.