Emission properties of the Er3+:4I11/2 → 4I13/2 transition in Er3+- and Er3+/Tm3+-doped Ge-Ga-As-S glasses

Ge-Ga-As-S glasses were investigated to develop efficient host materials for the Er3+:2.7 mum fiber lasers. Ge30Ga1As9S60 and Ge30Ga2As6S62 (all in at.%) glasses show good thermal stability and high rare-earth solubility up to 0.3 mol%. Mid-infrared emission with a peak wavelength of 2.76 mum and bandwidth of similar to 120 nm was observed in Er3+- and Er3+/Tm3+-doped Ge30Ga2As6S62 glasses. Codoping of Tm3+ significantly reduced the lifetime of the Er3+ : I-4(13/2) level due to the energy transfer of Er3+ : I-4(13/2) --> Tm3+ : F-3(4). Thus, the population inversion between the I-4(11/2) and I-4(13/2) levels in Er3+ became possible. In Er3+-doped glasses, the rate of cross-relaxation for the I-4(11/2) level was approximately ii times faster than that for the I-4(13/2) level. (C) 2000 Elsevier Science B.V. All rights reserved.