Superbroadband near-infrared emission in Tm-Bi codoped sodium-germanium-gallate glasses.

Superbroadband emission from 1.0 to 1.7 μm wavelength was observed in thulium-bismuth (Tm-Bi) codoped sodium-germanium-gallate (NGG) glasses under 793 nm excitation. Efficient energy transfer process from Bi to Tm ions, with value as high as 67.7%, was achieved which is beneficial in achieving flat broadband lineshape. The large stimulated emission cross-section and measured lifetime confirm the potentials of Tm-Bi codopants as luminescence sources for superbroadband near-infrared (NIR) optical amplifiers and tunable lasers. Planar optical waveguides were fabricated successfully in the codoped NGG glasses using K(+)-Na(+) ion-exchange process.