Emission properties of the [formula omitted] transition in Er 3+- and Er 3+/Tm 3+-doped Ge–Ga–As–S glasses

Abstract

Ge–Ga–As–S glasses were investigated to develop efficient host materials for the Er 3+:2.7 μm fiber lasers. Ge 30Ga 1As 9S 60 and Ge 30Ga 2As 6S 62 (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 μm and bandwidth of ∼120 nm was observed in Er 3+- and Er 3+/Tm 3+-doped Ge 30Ga 2As 6S 62 glasses. Codoping of Tm 3+ significantly reduced the lifetime of the Er 3+: 4 I 13/2 level due to the energy transfer of Er 3+: 4 I 13/2→ Tm 3+: 3 F 4 . Thus, the population inversion between the 4 I 11/2 and 4 I 13/2 levels in Er 3+ became possible. In Er 3+-doped glasses, the rate of cross-relaxation for the 4 I 11/2 level was approximately 11 times faster than that for the 4 I 13/2 level.