Lasing at 2.72 µm in an Er3+-doped high-purity tungsten–tellurite glass fiber laser

This Letter reports the experimental realization, for the first time to our knowledge, of lasing in an erbium-doped tellurite fiber at 2.72 µm. The key to the successful implementation was the use of advanced technology for obtaining ultra-dry preforms of tellurite glasses, as well as the creation of single-mode Er3+-doped tungsten–tellurite fibers with an almost imperceptible absorption band of hydroxyl groups, with a maximum of ~3 µm. The linewidth of the output spectrum was as narrow as 1 nm. Our experiments also confirm the possibility of pumping the Er-doped tellurite fiber with a low-cost high efficiency diode laser at 976 nm.