Submarine cables carry internet connections across the world, but their construction is less familiar than their role. The lines on the seafloor face risks ranging from accidental damage by ships and sabotage to shark bites and hazards posed by the terrain. Because repairs are costly and difficult, the cables are built with several protective layers.
A cable can be nearly as thick as an arm. Its outer shield is made of polyethylene, followed by polyethylene terephthalate tape, which provides tensile strength and electrical insulation. Braided steel wires add further protection and rigidity.
Deeper inside, a layer of aluminium helps block water, followed by polycarbonate, an aluminium or copper tube, and another water-resistant layer made with petroleum jelly. At the centre are the fibre-optic strands that carry data. The number of strands varies according to a cable’s transmission capacity.
The article cites Meta’s planned Petal submarine cable as an example: the project is expected to be completed in 2029 and is set to have 96 fibre pairs and a capacity of 1 petabit. Exact designs can vary by manufacturer, but the overall aim is the same: to protect the fibre-optic core from threats in the marine environment.
Sources: Xataka Móvil.