Optical interferometry–based array of seafloor environmental sensors using a transoceanic submarine cable

TLDR

Optical fiber‑based sensing can transform Earth observations by using existing submarine cables as seafloor sensors, yet prior interferometric methods only measured integrated changes over entire cable lengths up to 10,500 km. The study demonstrates detection of earthquakes and ocean signals on individual spans between repeaters of a 5,860‑km transatlantic cable rather than the whole cable. By applying this technique to existing undersea communication cables, whose repeater‑to‑repeater spans are 45–90 km, the largely unmonitored ocean floor can be instrumented with thousands of permanent real‑time environmental sensors without altering the underwater infrastructure. This approach enables thousands of permanent real‑time environmental sensors on the ocean floor without modifying the existing cable infrastructure.

Abstract

Optical fiber-based sensing technology can drastically improve Earth observations by enabling the use of existing submarine communication cables as seafloor sensors. Previous interferometric and polarization-based techniques demonstrated environmental sensing over cable lengths up to 10,500 kilometers. However, measurements were limited to the integrated changes over the entire length of the cable. We demonstrate the detection of earthquakes and ocean signals on individual spans between repeaters of a 5860-kilometer-long transatlantic cable rather than the whole cable. By applying this technique to the existing undersea communication cables, which have a repeater-to-repeater span length of 45 to 90 kilometers, the largely unmonitored ocean floor could be instrumented with thousands of permanent real-time environmental sensors without changes to the underwater infrastructure.