| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a high quality optical fiber wherein the variation in the outsider diameter is suppressed as much as possibly by suppressing the turbulence of gas stream in a drawing furnace. SOLUTION: The subject method for manufacturing the optical fiber is carried out by arranging an optical fiber preform in a drawing section 17 of a cylindrical core tube 12 provided in a furnace body 14 and heating to melt the optical fiber preform 18 by a heater 16 mounted in a core tube outside space 32b present between the furnace body 14 and the core tube 12 and drawing the optical fiber preform 18. In such a case, gaseous nitrogen is supplied to the core tube outside space 32b, the difference between the pressure Pr of a working chamber which is a pressure around the drawing furnace 11 and the pressure P1 of the core tube outside space 32b is kept almost constant and the flow rate Q of the inert gas flowing into the drawing section 17 from the core tube outside space 32b is controlled to be almost constant. COPYRIGHT: (C)2006,JPO&NCIPI |
