Distributed acoustic sensing in submarine optical fibers

Submarine optical fiber cables have become a vital component of global communication infrastructure, handling more than 99% of intercontinental data traffic. While vital for our daily life, these cables are also vulnerable and can be damaged or disrupted by natural events such as earthquakes or landslides, unintentionally by fishing activities, and also by deliberate acts of sabotage or terrorism. In this paper, we show that Distributed Acoustic Sensing (DAS) on these cables, in combination with suitable machine learning models, offers significant potential to anticipate third party aggressions to the cable. Moreover, we also show that DAS in this scenario can become a valuable new way for obtaining geophysical information at the bottom of the ocean. We discuss some of the applications of DAS in understanding ocean dynamics, including precise observations of surface waves, currents, tides, and the nonlinear phenomena driving water mixing, all of which are crucial for climate change predictions.