Submarine cable

摘要

In an optical fibre submarine cable the ingress of hydrogen ions is reduced if not eliminated by at least one envelope which provides a barrier to hydrogen ions. In one embodiment a copper tape (L) is folded longitudinally around the cable core comprising strength member wires (G,H) split aluminium or coppr tube (E) and optical fibre package (A). The abutting edges (L') are seam welded with less than 0.1% skips. Preferably the folded copper tape is longitudinally welded while a loose fit and subsequently reduced in diameter to leave an accurately determined small annular gap between tubes E and F which is filled with a water blocking material that is highly viscose at ambient temperature and effectively glues the tubes together. In an alternative embodiment, or as a modification to the embodiment just described, the aluminium or copper tube (E) has its abutting edges (E') welded to a depth sufficient to provide the envelope (or a second such envelope) but insufficient to cause damage to the optical fibre package (A) through the heat from welding.