Abstract:
One embodiment of the disclosure relates to a method of making an optical fiber comprising the steps of: (i) exposing a silica based preform with at least one porous glass region having soot density of r to a gas mixture comprising SiCl4 having SiCl4 mole fraction ySiCl4 (preferably of less than 0.03) at a doping temperature Tdop such that parameter X is larger than 0.03 to form the chlorine treated preform, wherein X is defined as a function of density r, doping temperature Tdop, SiCl4 mole fraction ySiCl4, and the density ps of the fully densified soot layer; and (ii) exposing the chlorine treated preform to temperatures above 1400 °C to completely sinter the preform to produce sintered optical fiber preform with a chlorine doped region; and (iii) drawing an optical fiber from the sintered optical preform.