Optical spectroscopy of Pr3+ ions in sol-gel derived GeO2SiO2 planar waveguides

A GeO2-SiO2 planar waveguide, activated with 1% mol Pr3+, has been prepared using a dip-coating technique. The GeO2-SiO2 film was deposited on a subst rate consisting of a silicon wafer with a silica buffer layer. After anneal ing at 800 degrees C and 900 degrees C the waveguide luminescence and Raman spectra were measured. The Raman spectra show that complete densification is achieved after annealing at 800 degrees C. Analysis of the emission spec tra and the decay curves from the P-3(0) and D-1(2) states of Pr3+ indicate s that the non-radiative relaxation due to the rare-earth clustering is les s important than in massive silica xerogels. (C) 1999 Elsevier Science B.V. All rights reserved.