Ytterbium doped sodium phosphotellurite glasses are made with different Yb3+ concentrations. Physical properties of the new glasses are reported. The glasses show high absorption and emission cross-sections and higher lifetime of [equation] transition. Laser performance parameter σe × τf, with a value as high as 2.14×10-20 cm2-ms and the laser threshold intensity as low as 1.79 KW/cm2 are reported. The laser parameters of these Yb3+ doped glasses show that they are potential to fabricate high power laser and broadband optical amplifiers.