Speaker verification in mismatch training and testing conditions.

Disclosed herein is a low phonon energy glass and a fiber made therefrom. The glass includes the following components given in mol percent: - germanium 0.1-30 - arsenic 0-40 - X 0.01-20 - Y 40-85 - wherein X is selected from the group consisting of gallium, indium and mixtures thereof wherein Y is selected from the group consisting of selenium, and mixtures of selenium and up to 50% of sulfur substituted for selenium and the glass also contains 0.001-2 weight percent of a rare earth, based on the weight of said components. The fiber has a minimum loss of less than 5 dB/m.