Effect of H-2/O-2 ratio on the GeO2 concentration profile in SiO2 : GeO2 glass preforms prepared by vapor-phase axial deposition

摘要

GeO2 radial concentration in silica glass preforms, prepared by vapor-phase axial deposition (VAD) method, was analyzed by X-ray fluorescence (XRF) measurements. The results were used to evaluate the effect of the H-2/O-2 ratio used during the deposition process in the formation of the GeO2 concentration profile. Considering four different H-2/O-2 ratios, GeO2 distribution was observed to decrease monotonically with the increasing radius for H-2/O-2 less than or equal to 1.5, and the acute shape around the core center of the GeO2 concentration profile, decreased with increasing H-2/O-2 ratio. When the ratio H-2/O-2 = 2.5, the central doping of GeO2 was minimal, and a constant distribution was obtained along glass preform radii. The results seem to indicate that the control of spatial distribution in the concentration of GeO2 deposited is favorable for the ratio H-2/O-2 less than or equal to 1.5. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 9]