METHOD FOR MAKING OPTICAL FIBER PREFORM HAVING ULTIMATELY LOW PMD THROUGH IMPROVEMENT OF OVALITY

摘要

A method for making an optical fiber preform having an ultimately low PMD (Polarization Mode Dispersion) through improvement of ovality is provided. This method has several collapse steps for collapsing an optical fiber preform having a clad/core deposition layer formed in a preform tube in which a rate of collapse is 0.01~0.06 mm/min at each collapsing step. By using this method, ovality and PMD of the optical fiber preform may be improved.