| 摘要 |
PURPOSE:To obtain the waterproof optical cable which has stable optical transmission characteristics over a wide temperature range by coating the peripheral surface of a tensile strength body with a thermoplastic water-absorptive swelling layer made of thermoplastic resin with high water absorptivity. CONSTITUTION:The optical cable has the tensile strength body 2 in the center and the peripheral surface of the tensile strength body is coated with the thermoplastic water-absorptive swelling layer 3 of a polyacryl acid material, etc., with high water absorptivity. Consequently, even if no waterproof admixture is used and water enters the optical cable, the water-absorptive swelling layer 3 between the tensile strength wire 2, a loose tube 5, etc., and an optical fiber wire 1, absorbs water and swells to prevent the water from entering the cable. Specially, when a loose tube type optical fiber is used, the friction against the loose tube is secured sufficiently, so the loose tube is prevented from expanding or contracting with temperature and the optical transmission characteristics of the loose tube become stable over a wide temperature range. |
