BlueLink: A Bidirectional Optical Modem for High-Speed Underwater Communication

Free space optical communication has emerged as a highly promising solution for enabling high-speed data transmission in underwater environments. The increasing demand for telemetry in unmanned underwater vehicles requires a significant increase in bandwidth capacity, surpassing the limitations of conventional acoustic technologies that currently dominate this domain. In this paper, we introduce a compact and energy-efficient optical modem for high-speed wireless underwater communication. The proposed modem offers bidirectional data transfer capabilities through the integration of transmitting LEDs and a photodiode receiver for light pulse detection, with data processing efficiently managed by an FPGA. The modem utilizes a software-defined architecture, enabling re-configurable modulation schemes and streamlining the implementation of signal filtering and processing through software, as opposed to traditional analog circuitry. Experiments conducted in a 3-meter seawater pool demonstrate a throughput of 2 Mbit/s.