Submarine fiber optic cable types

I well remember those horrible French made cables full of tar and other (expletive) whilst working for BT Marine in the jointing systems, especially redeveloping the x-ray camera to use newer smaller higher power emitter tubes. Horrible to work with and joint, especially with the French manual fusion welder (1 in 10 chance it would join the core correctly), the Japanese auto fusion welder had a better than 99% success rate.

The dielectric core insulation had to be over-moulded when jointing as the 'king wire' runs in the Kilo-Volt range near to shore, as the volt drop mid ocean is so severe, it powers the repeaters/boosters. Over moulding is done by injection moulding, with the core 'spool' centred in a teflon coated brass mould, if the jointer forgot the sleeves or sheave running taper sections it meant cutting the whole lot out and rejointing again, similarly if the x-ray showed voids in the over-mould it had to be cut out and redone as it would collapse and allow salt water in that would short the power as a minimum, even non-powered cables needed such joints as water degrades fibre transmissibility. https://www.sciencedirect.com/scienc...25540878900296 And is the reason much of the World's already installed but not yet used, aka 'dark fibre' is thought to be useless.

Submarine fiber optic cable types - photo