Amplification and lasing at 1.3 mu m in praseodymium-doped fluorozirconate fibres

Light emission from the ¹G₄ to ³H₅ transition around 1.3 mu m of Pr³⁺ has been studied in fluoride glass (ZBLAN) fibres. Pumping at 1064 nm yields extracted laser power of a few mW at 1.294 mu m. Gain curves centred at 1.295 mu m have been obtained, with gross gains of more than 15 dB at 1.319 mu m. Changes of the output ASE with pumping conditions are explained by excited state absorption or energy transfer from the ¹G₄ upper level of the transition.