There was a paper in science [1] this year looking at seismic events over a submarine link. The fibre also doesn't need to be dark in fact. [1] https://science

There was a paper in science [1] this year looking at seismic events over a submarine link. The fibre also doesn't need to be dark in fact. [1] https://science.sciencemag.org/content/371/6532/931 https://science.sciencemag.org/content/371/6532/931