Abstract: The cable consists of a central core including helical grooves at its periphery and a composite sheath. Each groove receives at least one optical fibre. To obviate any distortion near the optical fibres as a result of cable laying and of high isostatic pressures in operation of the order of 8 daN/mm.sup.2, the center of the core is constituted by a strand of metal wires and by a metal grooved jacket therearound. The sheath comprises a metal inner jacket which closes the grooves but does not press on the fibres, an insulting jacket, a second metal jacket and an outer insulating jacket.