Abstract: An optical fiber unit for air blown fiber installation, including an optical fiber wire; an inner coating layer formed on an outer periphery of the optical fiber wire with a modulus of elasticity ranging from 0.98 to 196 MPa; an outer coating layer formed on an outer periphery of the inner coating layer with a modulus of elasticity ranging from 196 to 1960 MPa; and a foamed plastic layer formed on an outer periphery of the outer coating layer.

Abstract: A resin liquid is provided which is used to produce an optical fiber coating layer which does not degrade over time in long-period transmission characteristics of the optical fiber. An optical fiber in which long-period transmission characteristics do not degrade is also provided. In order to achieve these objects, the present invention provides a resin liquid for an optical fiber coating layer containing at least one resin, wherein the resin liquid contains fewer than 500 pieces of extraneous material per 1 ml of the resin liquid, which have a minimum length of 0.5 ,&mgr;m or more and a hardness greater than a hardness of the resin liquid after curing.

Abstract: A single optical fiber tight cord having durable surface which is not cracked even under bending stress is described. The single optical fiber tight cord comprises a optical fiber; a plurality of glass fibers which are located around said optical fiber in parallel with said optical fiber; a UV curable resin provided around said optical fiber together with said glass fibers for fixing said glass fibers around said optical fiber; a UV curable resin layer covering and fixed around said optical fiber; and an outermost layer covering and fixed around said UV curable resin layer and made of a resin which is more excellent than said UV curable resin layer in tractility.

Abstract: The present invention provides a simple method for fixing a protective tube covering an optical fiber extending from an end of an optical fiber sheet to the optical fiber sheet. The method comprises the steps of: abutting the protective tube against the end of the optical fiber sheet; setting metallic molds so as to surround the abutted portion of the protective tube and the end of the optical fiber sheet; and injecting a hot-melt resin into the metallic molds so as to cover the abutted portion with the hot-melt resin. According to this simple method, the protective tube can be fixed to the optical fiber sheet with a sufficient strength.

Abstract: A disc reproducing includes, a motor for driving the disc, a turntable coupled to a motor shaft of the motor, a motor base for mounting the motor, a chassis for supporting the motor, a motor base bearing system mounted on the chassis for bearing the pendulum swing of the motor base above the chassis around a first axis along a trace of a beam spot of an optical pickup to a disc placed on the turntable and the flapping of the motor base around a second axis on the motor base for intersecting at the right angle the beam spot trade in parallel with the disc surface, a device for holding the motor base on the motor base bearing system, a first adjusting member mounted on the chassis for adjusting the pendulum swing attitude of the motor base around the first axis and a second adjusting member mounted on the chassis for adjusting the flapping attitude of the motor base around the second axis.

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.