Rare-earth doped chalcogenide glasses for fiber-optic amplifiers

Emission properties associated with the fiber-optic amplification in Ge–Ga–S–CsBr glasses were investigated. The intensity of the 1.31 μm emission from Dy3+ (6F11/2 · 6H9/2 → 6H15/2) increased sharply when the appropriate concentrations of alkali halides were added, at the expense of the 1.75 μm emission intensity (6H11/2 → 6H15/2). The lifetimes of the 1.31 μm emission level also increased up to 1580 μs. A small amount of As was added to increase the resistivity against the recrystallization during re-heating. The optimum composition for practical usage was 0.7[Ge0.25As0.10S0.65]–0.15GaS3/2–0.15CsBr. Phonon side band 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 tetrahedral [GaS3/2Br]− subunit and/or Ga2Br6. [Copyright &y& Elsevier]