Underwater Optical Backscatter Communication using Acousto-Optic Beam Steering

Accepted to SIGGRAPH Asia (ACM ToG)

Abstract: We present a high-speed underwater optical backscatter communication technique based on acousto-optic light steering. Our approach enables underwater assets to transmit data at rates potentially reaching hundreds of Mbps, vastly outperforming current state-of-the-art optical and underwater backscatter systems, which typically operate at only a few kbps. In our system, a base station illuminates the backscatter device with a pulsed laser and captures the retroreflected signal using an ultrafast photodetector. The backscatter device comprises a retroreflector and a 2MHz ultrasound transducer. The transducer generates pressure waves that dynamically modulate the refractive index of the surrounding medium, steering the light either toward the photodetector (encoding bit 1) or away from it (encoding bit 0). Using a 3-bit redundancy scheme, our prototype achieves a communication rate of approximately 0.667 Mbps with an energy consumption of $\leq 1 \mu \text{J}$, representing a 60$\times$ improvement over prior techniques. We validate its performance through extensive laboratory experiments in which remote underwater assets wirelessly transmit multimedia data to the base station under various environmental conditions.

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The repository contains codes used to convert the binary messages(video, image and auido) to a waveform useful for vibrating ultrasound which inturn encodes the data into the retroreflected beam.

Additional instructions are presented in the src folder, with how the data is transmistted through the PCIE signal generator and read through the Picoscope OSC.