Rare-earth doped chalcogenide glasses for fiber-optic amplifiers

Emission properties associated with the fiber-optic 6 amplification in Ge-Ga-S-CsBr glasses were investigated. The intensity of the 1.31 mum emission from Dy3+ (F-6(11/2) . H-6(9/2) --> H-6(15/2)) increased sharply when the appropriate concentrations of alkali halides were added, at the expense of the 1.75 mum emission intensity (H-6(11/2) --> H-6(11/2)). The lifetimes of the 1.31 mum emission level also increased up to 1580 mus. 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]-0.15GaS(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 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. (C) 2003 Elsevier B.V. All rights reserved.