Lasing parameters of ytterbium-doped fibres doped with P2O5 and Al2O3

Absorption and emission cross sections are measured for the ²F_5/2 → ²F_7/2 transition in Yb³⁺ ions in silica fibres doped with Al₂O₃ and P₂O₅. The measurements were performed by methods based on spectroscopic data and by more direct methods based on laser-transition saturation. Possible lasing ranges of ytterbium-doped double-clad fibre lasers are calculated from the measured spectral dependences of stimulated transition cross sections.