Patent ID: 6859606

Claim:
A boro-tellurite glass composition comprising the following ingredients: TeO 2 from 50 to 70 mole percent, B 2 O 3 from 5 to 22 mole percent, R 2 O from 5 to 25 mole percent, MO from 0 to 15 mole percent, A 2 O 3 from 5 to 18 mole percent, GeO 2 from 0 to 7 mole percent, and L 2 O 3 from 0.25 to 10 weight percent, wherein R 2 O is selected from the oxides Li 2 O, K 2 O, Na 2 O and mixtures thereof, MO is selected from the oxides BaO, MgO, CaO, ZnO and mixtures thereof, A 2 O 3 is selected from Al 2 O 3 , Y 2 O 3 and mixtures thereof, and L 2 O 3 is selected from rare earth oxides Er 2 O 3 , Yb 2 O 3 , Tm 2 O 3 , Tb 2 O 3 , CeO 2 , Sm 2 O 3 and Nd 2 O 3 and mixtures thereof.