Spectra and laser properties of Er3+,Yb3+ :phosphate glasses

The effects of Al2O3, Yb2O3, Er2O3 and OH on spectral properties Of P2O5.Na2O.SrO.Al2O3.Yb2O3.Er2O3 erbium phosphate glass were studied. 5, 8, 13 mol% Al2O3, 4, 5, 6, 7 and 8 mol% Yb2O3 and 0.05, 0.2, 0.4 mol% Er2O3 were used. It was found Al2O3 improves fluorescent lifetime of Er3+ ions, but the integrated absorption cross-section of Er3+ ions decreases with the increase of Al2O3 concentration. Evaluating from energy transfer efficiency of Yb3+ to Er3+ and spectral parameters of Yb3+ and Er3+, lower Al2O3 content, 6 mol% Yb2O3 and 0.2-0.4 mol% Er2O3 are preferred for LD pumped microchip laser application. OH groups in glass greatly affect fluorescent intensity and lifetime of Er3+, Yb3+ :phosphate glass. The OH absorption coefficient at 3000 cm(-1) should be < 1 cm(-1) for laser applications. Pumped with a 2 W, 974 nm InGaAs laser diode, CW laser centered at 1530 nm with slope efficiency of 10.6% and maximum output of 43 mW was achieved in our 2 mm thick Er3+, Yb3+ :phosphate glass at room temperature. (C) 2002 Elsevier Science B.V. All rights reserved.