The tetraphosphate glasses with various Yb3+ dopant were prepared. The abso
rption and fluorescence emission spectra were measured. The spectroscopic p
roperties and laser performance parameters of Yb3+ in tetraphosphate glasse
s were calculated. The disagreement between the reciprocity method and Fuch
tbauer-Ladenburg formula was discussed using the radiation trapping effect.
The effects of Yb3+ and OH- contents on emission properties were investiga
ted. The result shows that Yb3+ -doped tetraphosphate glass exhibits excell
ent spectroscopic properties.