Properties of Tm3+-Doped Germanotellurite Glasses for S-Band Amplifier

Optical and material properties of (75− x )TeO₂– x GeO₂–20ZnO–5Na₂O–0.1Tm₂O₃ glasses were investigated as candidate materials for an S-band Tm-doped fiber amplifier (TDFA). With increasing GeO₂ content, the lifetime and the quantum efficiency of the 1.46 μm emission decreased slightly, while the emission bandwidth, the Vickers hardness, and thermal stability of the glass improved monotonically. Above 20 mol% GeO₂, the quantum efficiency decreased more rapidly with increasing GeO₂. We conclude that addition of a small amount of germania may improve material properties without deteriorating the optical properties of doped Tm³⁺, and thus the germanotellurite fiber may be a more reliable material for the S-band TDFA in wavelength-division-multiplexing telecommunication.