Non radiative relaxation rate modification by chlorine codoping of rare earth activated PZG fluoride glasses

The luminescence of rare earth ions Re3+ = Pr3+, Er3+, and Tm-3 in PZG fluoride glass (36PbF(2)-24ZnF(2)-35GaF(3)-5YF(3)-2AlF(3) in mol%) doped with ReCl3 was investigated. This study was initiated in the perspective of realizing by vapor phase deposition (PVD) rare earth activated fluoride glass channel waveguides acting as integrated optical amplifiers, ReCl3 being more volatile than the fluoride counterpart. The results were compared to the spectroscopic properties of ReF3-doped PZG glasses. For phonon-sensitive radiative transitions, the lifetime was prolonged at low ReCl3 concentration because of phonon energy and/or electron coupling are reduced. For Pr3+, the doping with PrCl3 increases the lifetime by 50% in respect to PrF3 doping. These results suggest that the chlorine ions remain in the coordination sphere of the rare earth ions in the ReCl3-doped glass after melting. The luminescence decay of Er3+: I-4(13/2) level in ErCl3-doped channel waveguides is also discussed.