Watertight multi-core fibre-optics communication cable

摘要

A watertight multiple glass fibre core cable, in which optical glass fibres are freely mobile in a sheath, has its glass fibre cores stranded around or laid in oscillating manner on a central swellable yarn which preferably has a maximum swollen diameter 5-10% smaller than the inside diameter of the cable sheath. Also claimed is a method of producing the above cable by means of a single operation of forming the assembly of cores and swellable yarn by stranding or oscillation, using a turn length or number of turns per unit time to produce an excess length of cores within the sheath, and sheathing by extrusion with air injection to improve the shape stability of the cable in the sheath.