Pr3+-doped Ge-S-I glasses as candidate materials for 1.3 mu m optical fiber amplifiers

Pr3+-doped Ge-S-I samples, with compositions having an S/Ge ratio between 1.5 and 1.7 and iodine concentrations between 5 and 20 at.%, have been prepared by well-established glass-melting techniques. The thermal and spectroscopic properties of these glasses have been measured and evaluated to assess their suitability for a fiber amplifier application at 1.3 mu m. Pr3+ ions were successfully dissolved in Ge35S56.5I8.5 glass at doping levels as large as 0.2 wt%. The glasses within the investigated compositional range are transparent at the excitation (1.02 mu m) and emission (1.34 mu m) wavelengths for Pr3+ ions. The (1)G(4)-H-3(5), emission band of Pr3+ had a peak at 1.344 mu m and an effective linewidth of 85 nm in this host. A (1)G(4) level fluorescence lifetime of 368 mu S was measured in a 500 ppm/wt Pr3+-doped Ge35S56.5I8.5 samples. Glass rods of Pr3+-doped Ge35S56.5I8.5 composition, with typical 5 cm lengths and 10 mm diameters, were produced for fiber drawing.