980-nm diode-pumped Tm^3+?Yb^3+-codoped tellurite fiber for S-band amplification

We report gain measurements in Tm(3+)/Yb(3+)-codoped tellurite glass fibers in the 1460-1530-nm region using a conventional 980-nm pumping scheme. The gain spectrum is dependent on the geometry of the fiber and the length owing to the superfluorescence upconversion pump scheme.