FIBRE OPTICS: Lasing parameters of ytterbium-doped fibres doped with P2O5 and Al2O3

Absorption and emission cross sections are measured for the 2F5/2 ? 2F7/2 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.