Did you ever read “Blind Man’s Bluff”? Great book about submarine warfare including interception of marine optical cable comms.
It’s on my shelf in sight! Yes, read it. And that was in the “olden days.”
Plus, that was far more tricky, intercepting cable comms.
Cutting the cables with cross-laid explosive linear charges fed out of a sub will be 1,000X easier.
Our own FReeper, LS, wrote a book about submarines — one of DH’s favorites.