Abstract:
A method for forming an optical fiber includes drawing at a high draw rate, e.g. preferably > 10m/s the optical fiber from a glass preform and treating (annealing or slow cooling) the fiber by maintaining the optical fiber within a treatment temperature range for a short treatment time, e.g. 830 ° C/s and
Abstract:
A method for forming an optical fiber includes drawing at a high draw rate, e.g. preferably ⊃ 10m/s the optical fiber from a glass preform and treating (annealing or slow cooling) the fiber by maintaining the optical fiber within a treatment temperature range for a short treatment time, e.g. ∫ 0-5 s.Preferably the fiber is cooled at a specified cooling rate of ⊃ 830 ° C/s and ∫ 4000 ° C/s.The optical fiber treatment reduces the tendency of the optical fiber to increase the attenuation due to Rayleigh scattering, and/or over time following formation of the optical fiber due to heat aging.Apparatus are also provided and comprise a muffle or heat-aging tube immediately downstream of the draw furnace exit, preferably attached there to and sealed to prevent entry of ambient air.Means for supplying gas, e.g. He, to the draw furnace and another gas, e.g Ar and N2 to the muffle or heat-aging tube for annealing or slow cooling the draw fiber.