If you are experiencing problems downloading PDF or HTML fulltext, our helpdesk recommend clearing your browser cache and trying again. If you need help in clearing your cache, please click here . Still need help? Email email@example.com
Germanium-doped silica soot particles from the Vapor-phase Axial Deposition (VAD) process were taken from unconsolidated light-guide preform boules and characterized by infrared spectroscopy, light scattering, x-ray diffraction, ICP elemental analysis, and TEM examination. The results
show that while GeO2 concentration decreases with increasing radius as required for the light-guiding refractive index profile, the fraction of the GeO2 in the crystalline form increases with increasing radial position in the boule. Infrared spectra are consistent with
most of the soot particles containing separate phases of partially crystalline GeO2 and amorphous SiO2 as opposed to a compound glass. The light scattering by particles suspended in media of various refractive indices is that expected from inhomogeneous particles, as
required for the two-phase model. Water solubility experiments followed by infrared or ICP analyses confirm this model and further support a detailed structure for the particles in which the separate GeO2 phase is present as a shell or coating on a predominantly silica core. Particles
have sizes ranging from 10 to more than 125 nm, and they are mostly spherical in shape. Near the center of the boule, however, where substrate temperatures are higher for longer times, partially fused chains of spherical particles are found, and the sizes and shapes of the particles in both
regions are consistent with growth by Brownian coagulation.
AT&T Bell Laboratories, Murray Hill, New Jersey 07974 2:
AT&T Bell Laboratories, Murray Hill, New Jersey 07974; present address: ERC, Princeton, NJ 08540
Publication date: February 1, 1988
More about this publication?
The Society publishes the internationally recognized, peer reviewed journal, Applied Spectroscopy, which is available both in print and online. Subscriptions are included with membership or can be purchased by institutional or corporate organizations. Abstracts may be viewed free of charge. Previously published as Bulletin (Society for Applied Spectroscopy)