DRAW CONSTANT DOWNFEED PROCESS

摘要

Optical fiber (14) is drawn from a preform (10) that is fed to a furnace at a constant downfeed rate. The optical fiber (14) is drawn by a tractor (20) at a rate of at least 10 meters per second and the tractor (20) is allowed to vary the draw speed of the fiber (14) based on the fiber diameter as measured by a diameter monitor (15) during the draw processing in order to maintain a relatively constant fiber diameter. Maintaining the preform downfeed rate constant even at high draw rates in excess of 20 meters per second does not adversely effect the draw process and is believed to reduce or eliminate oscillations in the draw control loop that can cause variations in the core shape during fiber formation, resulting in reduced PMD and improved MFD uniformity.