Abstract: Five kinds of erbium doped phosphate glass samples named WM1～WM5 with different contents of
Al₂O₃, Na₂O, La₂O₃, Y₂O₃ and AlF₃ were prepared, and their chemical durability, thermal, mechanical and spectroscopic properties
were investigated. The chemical durability of these glasses was tested by immerging the samples in boiling water. The results obtained show that
the glass with Al₂O₃ content of 9.8wt% has the best chemical durability and has the highest Knoop hardness, higher glass transition temperature and lower thermal
expansion coefficient. Al₂O₃ greatly improves the chemical durability of phosphate glass. AlF₃ deteriorates the chemical
durability of the glasses a little. For improving thermal stability, Y₂O₃ is better than La₂O₃. The spectral properties of Er³⁺ in these glasses
were evaluated by measuring their absorption and emission spectra and fluorescence lifetime. The glass with 9.8wt% Al₂O₃ has the largest
absorption cross section for both Yb³⁺ and Er{3+ ions. Based on chemical durability, thermal, mechanical and spectral properties, WM1 glass
, containing 9.8 wt% Al₂O₃ and 6.9 wt% Na₂O, is the best candidate for ion exchange processing.

Key words: erbium, phosphate glass, ion exchange, waveguide amplifier