Liq. filled cables - for trans:oceanic undersea optical fibre communications protect optical cables around a steel core cable from hydrostatic crushing

摘要

Undersea telecommunications cable using optical signal fibres is made by grouping the optical fibres in an annular array around a core cable made of high tensile steel cables and enclosed in a tight-fitting sleeve of high electrical conductivity (cu). The optical fibres are contained in an oversize jacket of an impermeable thermoplastic material (polyethylene) in which the interstitial space if filled with a dielectric liq. having a density similar to that of water. Repeater units' have terminals which secure the core cable and the sheath of the signal cable and admit the signal cables via seals which can exclude the dielectric fluid filling the cable. Used for submarine cables requiring sufficient tensile strength for deep sea laying, sufficient compressive strength to resist the hydrostatic pressure and which can incorporate repeater units to boost the signal and to localise the position of any faults or breaks in the cable.