DEVICE AND METHOD FOR DRAWING OPTICAL WAVEGUIDE FIBER

摘要

PROBLEM TO BE SOLVED: To provide a method and device for drawing an optical waveguide fiber which minimizes the fiber bow induced by the deviated stress in the clad layer of the fiber. SOLUTION: The fiber 11 is drawn from a preform 20 heated in a drawing furnace 12. The gas introduced into the top 21 of the furnace advances through the inside of the furnace 12 into a tube 31 and forms a boundary layer adjacent to the fiber. The tube 31 isolates the fiber 11 from the ambient atmosphere and the boundary layer of the gas formed in the furnace is maintained in a substantially uniform state until the temperature sufficiently high for the viscosity of the clad layer of the fiber to minimize the deviated stress in the circumferential direction of the fiber is attained.