Spectroscopic properties and local structure of rare-earth ions in Ge-Ga-S glasses with the addition of alkali halides were investigated. The intensity of the 1.31-μm emission from Dy³⁺ (⁶F_11/2·⁶H_9/2 ⁶H_15/2) increased sharply when the appropriate amount of alkali halides was added, at the expense of the 1.75-μm emission intensity (⁶H_11/2 ⁶H_15/2). The lifetimes of the 1.31-μm emission level also increased as much as 35 times from 38 μs for Ge-Ga-S glass (0.1 at.% Dy³⁺) to 1320 μs for glass containing 10 mol% of CsBr. These enhancements occurred only when the ratio of MX(M = K,Cs and X = Br, I)/Ga was equal to or larger than unity. Phonon side band (PSB) showed that the several local phonon modes, with the frequencies around 100 cm^-1, were coupled to 4f electrons of Eu³⁺. The nearest neighbors of Eu³⁺ ions are composed of halogen ions that are part of well-structured complex such as EuCl₃, tetrahedral GaS_3/2Cl ^- subunit and/or Ga₂Cl₆. A small amount of As was added to increase the resistivity against the recrystallization during re-heating. The best composition for practical usage was 0.7 Ge_0.25As_0.10S_0.65 -0.15 GaS_3/2-0.15 CsBr. This glass also exhibited high resistance against the attack of liquid water and is therefore a potential material for efficient fiber-optic amplifiers.

Les propriétés spectroscopiques et les environnements locaux des terres rares dans des verres à base de Ge-Ga-S modifiés par des halogénures alcalins sont présentés. Les caractéristiques de certaines émissions comme celle du dysprosium à 1,31 μm ou de l'europium sont particulièrement discutées.