Signal amplification in rare-earth doped heavy metal germanium tellurite glass fiber

Rare-earth doped heavy metal germanium tellurite (NZPGT) glass fibers with lower maximum phonon energy of 793 cm^-1 and UV-sensitivity property have been designed and fabricated. Bright and compact upconversion traces have been observed in Er³⁺=Yb³⁺ and Tm³⁺=Yb ³⁺ codoped NZPGT glass fibers, which exhibit favorable flexibility and excellent thermal stability, indicating that the NZPGT glasses are a desirable candidate for fiber amplifiers. The Er³⁺=Yb³⁺ codoped NZPGT glasses present a broad emission at ∼1:5μm with the FWHM of 72:7nm, and the maximum internal gain of 12:59dB witha remarkable gain coefficientof 2:38dB=cmin the C-band were achieved in a Er³⁺=Yb ³⁺ codoped NZPGT glass fiber. The efficient three-photon blue and two-photon near-IR upconversion emissions of a Tm³⁺=Yb³⁺ codoped NZPGT glass fiber demonstrate that low phonon energy NZPGT glasses have promising potential applications in Tm³⁺ single-doped glass fibers for S-band signal amplification, and the further development of O-and U-band fiber amplifiers and lasers in Pr³⁺ and Ho³⁺ doped NZPGT glass fibers.