| 摘要 |
PURPOSE:To suppress a change in the Young's modulus of a layer of a water absorbing ultraviolet-curing org. polymer having >=1wt.% water absorbing capacity on a quartz glass-base optical fiber by forming a layer of a water impermeable org. polymer on the water absorbing polymer layer. CONSTITUTION:A primary coating layer 2 and/or a secondary coating layer 3 on an optical fiber 1, especially the secondary coating layer 3 is made of a water absorbing ultraviolet-curing org. polymer and a water impermeable layer 4 is formed on the layer 3. The layer 4 is made of a water impermeable org. polymer. The water absorbing capacity and water permeability of the water impermeable polymer are <=1/5, preferably <=1/10 of those of the water absorbing polymer. Ultraviolet-curing fluororesin or polyvinylidene chloride may be used as the water impermeable polymer. Even when the relative humidity of an atmosphere in which the optical fiber is used undergoes a change, the diffusion of water into the water absorbing polymer layers 2, 3 is effectively hindered, so a change in the Young's modulus of the layers 2, 3 due to a change in the relative humidity can be suppressed.
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