PRODUCTION METHOD FOR OPTICAL FIBER

摘要

A drawing apparatus 1 has a drawing furnace 11, a heating furnace 21, and a resin curing section 31. The drawing furnace 11 has a muffle tube 13 to which an He gas supply passage 15 from an He gas supply section 14 is connected so as to supply He gas. The optical fiber 3 drawn upon heating by the drawing furnace 11 is fed to the heating furnace 21, whereby a predetermined part of the optical fiber 3 is annealed at a predetermined cooling rate. The heating furnace 21 has a muffle tube 23 to which an N2 gas supplypassage 25 from an N2 gas supply section 24 is connected so as to supply N2 gas. Thereafter, the optical fiber 3 is coated with a UV resin 39 by a coating die 38, and the UV resin 39 is cured in the resin curing section 31, whereby a coated optical fiber 4 is formed.