Pr3+-doped 1.3 μm optical fibre amplifiers in new GeS 2-based chalcogenide glasses

A new germanium sulphide glass has been synthesised as host material for praseodymium (Pr⁺³) doped 1.3 μm fibre amplifiers. The low phonon energy of germanium sulphide glasses makes them ideal candidates as host material for high-efficiency fibre amplifier devices. ¹G₄-³H₅ spontaneous emission spectrum and ¹G₄ fluorescence lifetime were measured in selected Pr⁺³-doped glass compositions and a quantum efficiency of 60% was calculated. Input data for fibre amplifier numerical modelling were provided by the optical characterization of Pr⁺³-doped glass samples. Incoherent signal contribution to the signal amplification process, such as amplified spontaneous emission (ASE), is also considered in order to design high efficiency low noise fibre amplifiers. In the small-signal regime a pump-gain conversion efficiency equal to 0.65 dB/mW was calculated, pointing out the efficiency of the designed fibre amplifier to convert the optical pump power into available signal gain