LOW LOSS OPTICAL FIBER AND METHOD OF MAKING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a low loss optical fiber and a method of making the same that are capable of providing improved viscosity matching between a core and a cladding during fiber draw while minimizing the amount of optical power that is present in the cladding.SOLUTION: A core region 12 of an optical fiber 10 is doped with chlorine in a concentration that allows the viscosity of the core region to be lowered to approach the viscosity of a surrounding cladding. An annular interface region 16 is disposed between the core and the cladding and contains a sufficient concentration of fluorine dopant to match the viscosity of the core. By including this annular stress accommodation region, the cladding layer can be formed to include a relatively high concentration of fluorine required to provide a desired degree of optical signal confinement.SELECTED DRAWING: Figure 1