Yg. Choi et al., Emission properties of the Er3+: I-4(11/2) -> I-4(13/2) transition in Er3+- and Er3+/Tm3+-doped Ge-Ga-As-S glasses, J NON-CRYST, 278(1-3), 2000, pp. 137-144
Ge-Ga-As-S glasses were investigated to develop efficient host materials fo
r the Er3+:2.7 mum fiber lasers. Ge30Ga1As9S60 and Ge30Ga2As6S62 (all in at
.%) glasses show good thermal stability and high rare-earth solubility up t
o 0.3 mol%. Mid-infrared emission with a peak wavelength of 2.76 mum and ba
ndwidth of similar to 120 nm was observed in Er3+- and Er3+/Tm3+-doped Ge30
Ga2As6S62 glasses. Codoping of Tm3+ significantly reduced the lifetime of t
he 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 righ
ts reserved.