Rare-earth doped chalcogenide glasses for fiber-optic amplifiers

Abstract 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 Dy 3+ ( 6 F 11/2 · 6 H 9/2 → 6 H 15/2 ) increased sharply when the appropriate concentrations of alkali halides were added, at the expense of the 1.75 μm emission intensity ( 6 H 11/2 → 6 H 15/2 ). 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[Ge 0.25 As 0.10 S 0.65 ]–0.15GaS 3/2 –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 Eu 3+ . The nearest neighbors of Eu 3+ ions are composed of halogen ions that are part of well-structured complex such as tetrahedral [GaS 3/2 Br] − subunit and/or Ga 2 Br 6 .