Abstract: An optical fiber cable that sustains reduced increase in transmission loss and optical fiber breakage when subject to external pressure exerted thereon, comprises an aggregate of elements including central buffer filaments disposed in the center part of the optical fiber cable and a plurality of optical fibers disposed around the central buffer filaments, as well as circumferential strength filaments disposed around the outer periphery of the aggregate of elements, and a sheath covering the circumferential strength filaments.

Abstract: Metal filaments such as steel wires which has Young's modulus of 10,000 kg/mm2 are provided longitudinally on a UV curable resin coated optical fiber. A resin covering layer is then formed on a resultant structure by coating ultraviolet curing resin and then curing the resin, whereby resulting in an extremely small optical fiber cord having a finished diameter of about 250 &mgr;m.

Abstract: The present invention relates to a method for the fusion splicing of carbon coated optical fibers and to a method for providing reinforced performance of the spliced points. Concretely, carbon coated optical fibers are fusion spliced in an atmosphere containing less than 0.5 vol % of oxygen without the removal of the carbon coating. In order to minimize the amount of damage to the carbon coating resulting from the fusion, the decline in the failure probability of the optical fiber is controlled by means of applying moisture to the spliced part or by means of the adhesion of the oxidized carbon gases to the optical fiber. On the other hand, the carbon coating layer which was removed by oxidation at the time of the fusion splicing is recoated by means of a CVD reaction using a laser as a heat source. By means of this, the decline in the fatigue characteristics of the spliced part can be controlled.

Abstract: The present invention relates to a method for the fusion splicing of carbon coated optical fibers and to a method for providing reinforced performance of the spliced points. Concretely, carbon coated optical fibers are fusion spliced in an atmosphere containing less than 0.5 vol % of oxygen without the removal of the carbon coating. In order to minimize the amount of damage to the carbon coating resulting from the fusion, the decline in the failure probability of the optical fiber is controlled by means of applying moisture to the spliced part or by means of the adhesion of the oxidized carbon gases to the optical fiber. On the other hand, the carbon coating layer which was removed by oxidation at the time of the fusion splicing is recoated by means of a CVD reaction using a laser as a heat source. By means of this, the decline in the fatigue characteristics of the spliced part can be controlled.

Abstract: A method for manufacturing carbon coated optical fiber includes the steps of removing adherent foreign material from a surface of a bare optical fiber, and forming at least one carbon layer on the surface thereof using a chemical vapor deposition method. The first step is performed by heating and drying the surface of the bare optical fiber in a 80 to 150 degrees C. temperature region to vaporize the adherent foreign material while supplying an inert gas to the surface thereof so as to substitute the inert gas for the vaporized adherent foreign material. The second step is performed by thermally decomposing at least one hydrocarbon compound to obtain a thermal decomposate of the hydrocarbon, and depositing the thermal decomposate on the surface of the bare optical fiber. Also, disclosed is a method for manufacturing carbon coated optical fiber including the steps of cooling a surface of a bare optical fiber to a temperature no higher than 50.degree. C.

Abstract: Disclosed is a method for producing carbon-coated optical fiber including the steps of thermally decomposing a halogenated hydrocarbon compound to obtain a thermal decomposate of the halogenated hydrocarbon, and depositing the thermal decomposate on a surface of an uncoated optical fiber to form at least one carbon coating layer on the surface of the fiber. The halogenated hydrocarbon compounds include CClF.sub.3 , CCl.sub.2 F.sub.2 , CCl.sub.3 F, C.sub.2 Cl.sub.2 F and C.sub.2 ClF.sub.5. The deposition is performed at a temperature which is slightly below the thermal decomposition temperature. The method includes an optional step of coating at least one resin layer over a surface of the carbon coating layer.

Abstract: There is disclosed an optical fiber coated with a carbon layer in which carbon coating layer is formed by thermally decomposing a hydrocarbon or halogenated hydrocarbon compound having 15 or less carbon atoms. There is also disclosed an apparatus for producing the optical fiber coated with at least one carbon layer.