Germanium nanocrystals CNC) are observed by Raman spectroscopy in germanosi
licate-core fibres previously loaded with hydrogen and annealed at temperat
ures above 1000 degreesC. The conditions of the appearance of the Ge NC Ram
an band in the optical fibres are described and possible mechanisms of thei
r formation are analysed. (C) 2001 Elsevier Science B.V. All rights reserve
d.