I asked a submarine guy how much the fibers
can carry because this sounded low to me. His response:
That was just an example to illustrate the commercial contracting,
not the technical capabilities.
Cables currently being laid in the sea are going in at anywhere
between 16 and 24 fibre pairs. The design capacity per fibre pair of
these systems is 20Tbps, with a possible 480Tbps of Shannon limit
capability.