Trivalent holmium-activated fluoride fiber for potential 1340 ∼ 1400 nm optical amplifiers

In summary, we propose that Ho³⁺ and Ho³⁺/Yb³⁺-doped fluoride glasses are a good candidate material for fiber amplifiers operating at the OH-band of silica fiber for optical transmission. Upconversion excitation in the wavelengths of 880-920 nm and 970-990 nm is achieved for Ho³⁺ single-doped glasses and 910-1000 nm for Ho³⁺/Yb³⁺-codoped glasses.