| 摘要 |
PURPOSE:To obtain an optical fiber prevented from moisture penetration and increase in transmission loss by forming a hermetic film, through a plasma of raw material gas under reduced pressure, on the surface of an optical fiber spun from a matrix. CONSTITUTION:An optical fiber 3 produced by spinning a matrix 1 melted by heating in a furnace 2 is introduced into a vacuum vessel 4 reduced in pressure to 0.1-1Torr and passed through respective pairs of raw material gas- emitting electrodes 5, 6. These electrodes 5, 6 are fed with a gaseous monomer via raw material feed pipes 9, 10, and, concurrently with this, a high-frequency voltage is applied between the electrodes 5, 6 form a high-frequency source 11 via an electric source line 12 to generate a plasma, with which a hermetic film 17 is formed on the surface of the optical fiber 3 followed by coating a polymeric resin film 18 thereon through a relevant coater 16. |
