| 摘要 |
PURPOSE:To improve the cooling effect in the cooling of a drawn optical fiber having high temperature even at a high drawing speed and to enable uniform coating with a resin by introducing a cooling gas into a cooling tube through a lower opening of the tube and forcedly exhausting the gas through an upper opening of the tube. CONSTITUTION:An optical fiber 4 produced by drawing an optical fiber preform 1 is cooled in a cooling tube 9 and the surface of the optical fiber 4 is coated with a resin in a polymer-coating tank 5. In the above process, a cooling gas (He gas) is introduced into the cooling tube 9 through an inlet port 93 opened on the side wall of the tube at a lower position and forcedly exhausted with a pump 95 through an exhaustion port 94 opened at an upper position on the side wall of the cooling tube 9. The intrusion of air into the cooling tube 9 can be prevented by this process and, at the same time, the flow out of the cooling gas from the lower end of the cooling tube 9 can be prevented to enable the cooling with the cooling gas in high efficiency. |
