Patent ID: 6851282

Claim:
A method of making an optical fiber, which draws an optical fiber preform upon heating and coats thus drawn optical fiber with a resin; said method comprising the steps of: drawing said optical fiber preform upon heating in an atmosphere constituted by a first gas having a predetermined thermal conductivity; heating and annealing said drawn optical fiber in an atmosphere constituted by a second gas having a thermal conductivity lower than said predetermined thermal conductivity of said first gas; coating said annealed optical fiber with said resin; supplying said first gas into an upper portion of a drawing furnace so that said first gas flows downward said drawing furnace; and discharging said first gas from a first gas exit section disposed between said drawing furnace and a heating furnace; and discharging said second gas from said heating furnace so that said first gas and said second gas are not mixed in said drawing furnace.