The excited state lifetime of Er<sup>3+</sup> and gain coefficient of an Er<sup>3+</sup>/Yb<sup>3+</sup> co-doped phosphosilicate optical fibre with and without hydrogen loading can be recovered and even improved by high temperature annealing. Consequently processes optimizing room temperature component fabrication such as hypersensitisation are found to offer no added value for high temperature operation. The implications for harsh environmental laser performance are discussed.
Broadband emission sources such as super luminous diodes and rare earth doped fibre for ASE sources have wide applications in optical fibre measurement and sensing systems. Recent intensive research has shown broadband luminescence in the range of 1100 to 1500 nm, across O, E and S bands of the telecommunications window from glasses or materials with Bi-doping and Bi/Er codoping. The broadband luminescence of active optical fibres in this wavelength range is particularly interesting for fibre amplifiers, lasers and ASE sources for optical communication and sensing applications. Here we report our recent development of Bi/Er/Al codoped phosphogermanosilicate optical fibre with ultra-broadband luminescence between 1000 to 1570 nm, covering O-, E-, S-, C-, and L-bands, when pumped by 532, 808, or 980 nm lasers. The new material composition of this optical fibres are potentially useful as gain media for ultrabroadband ASE sources, tunable fibre lasers or amplifiers.