METHOD AND APPARATUS FOR DRAWING OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To provide a method and an apparatus for drawing an optical fiber capable of spinning the optical fiber having reduced transmission loss and small variation of the outer diameter. SOLUTION: A furnace bottom tube 5 is provided successively at the lower end of a furnace core tube 2. An optical fiber preform 10 is suspended inside the furnace core tube 2 and the tip of the optical fiber preform 10 is melted by heating to reduce the diameter. The diameter reduced part 11 is positioned in the furnace bottom tube 5 and drawn upto the outer diameter of an optical fiber 12 while slowly cooling the diameter reduced part 11 by flowing a temperature adjusting-gas in the furnace bottom tube 5. The drawing conditions are controlled such that the diameter reduced part 11 reaches the target outer diameter of the optical fiber 12 within the furnace bottom tube 5 and the Reynolds number R of the temperature adjusting-gas flow is 1,000 or less. COPYRIGHT: (C)2003,JPO