Cooling and bubble-free coating of optical fibers at a high drawing rate

For economic reasons, the drawing rate of optical fibers should be as high as possible. However, a high drawing rate introduces problems with respect to on-line coating of the fiber such as insufficient cooling down of the fiber before coating and application of an absolutely bubble-free concentric coating layer. A cooling device and a force-feed coating applicator are described that enable proper coating of fibers at speeds of at least 700 m/min using a short drawing tower.