Method of making optical fiber

摘要

Fiber bow makes mass fusion splicing of optical fiber difficult and this is undesirable. We have found that fiber bow can be significantly reduced if the fiber that is being drawn from a heated optical fiber preform is caused to run through a tubular cooling chamber that extends from the draw furnace, the cooling chamber comprising a tube of inner diameter d1<35 mm, preferably <20 mm. In a preferred embodiment the cooling chamber includes an upper cooling chamber of inner diameter d2>d1, with a transition element providing a smooth transition between the two chambers. The cooling chamber desirably is free of turbulence-causing air leaks and/or geometrical features.