Er³⁺ doped Na₂O–Nb₂O₅–TeO₂ glasses for optical waveguide laser and amplifier

Er³⁺ doped Na₂O–Nb₂O₅–TeO₂ (NNT) glasses suitable for making optical waveguide devices has been fabricated and characterized. Intense 1.53 μm infrared fluorescence and green upconversion luminescence were observed under 975 nm diode laser and 798 nm laser excitation. The optical absorption, the Judd–Ofelt parameters and the spontaneous transition probabilities have been measured and calculated. The quantum efficiency of 1.53 μm emission band is proved to be ∼100%. The maximum emission cross-section is 1.02×10⁻²⁰ cm² at 1.533 μm, and it is more than 30% higher than the values in silicate and phosphate glasses. Under 798 nm excitation, strong green and weak red upconversion luminescence was observed at room temperature. The 546 nm green band shows a broad full-width at half-maximum of 16 nm. Intense and broad green upconversion fluorescence in Er³⁺ doped NNT glass can be used in colour display, undersea communication and infrared sensor. High concentration of Na₂O is a benefit to developing waveguide device from the glass.