M. Essid et al., Correlation between oxygen-deficient center concentration and KrF excimer laser induced defects in thermally annealed Ge-doped optical fiber preforms, J NON-CRYST, 246(1-2), 1999, pp. 39-45
The amplitude of the 5 eV optical absorption band of oxygen-deficient germa
nium-doped silica samples (3GeO(2):97SiO(2)) was varied by annealing in oxy
gen at 1000 degrees C for different periods of time. Each sample was irradi
ated with the same dose of 5 eV light from a KrF excimer laser to study the
effect of the absorption band amplitude on the photo-induced changes. ESR
(Electron spin resonance) and optical absorption measurements were carried
out after each annealing and each laser irradiation cycle. We find that sam
ples with an initially higher 5 eV absorption band amplitude exhibit a larg
er increase in the absorption bands related to the photo-induced paramagnet
ic Ge E' and GEC (Germanium Electron Center) when irradiated with the same
laser dose. Deconvolution of the measured spectra shows that the concentrat
ions of the photo-induced paramagnetic Ge E' and GEC defects are well corre
lated with the concentration of GLPC (germanium lone pair center) defects a
ssociated with a 5.14 eV absorption band. (C) 1999 Published by Elsevier Sc
ience B.V. All rights reserved.