Two-color pump schemes for Er-doped tellurite fiber lasers and amplifiers at 2.7-2.8 µm

We propose two-color pump schemes for CW Er-doped tellurite fiber lasers and amplifiers in the 2.7-2.8 µm range at the transition. The use of the first pump wavelength of 0.98 µm () or 1.56 µm () and the second pump wavelength of 1.7 µm () allows obtaining gain at relatively low powers. We have performed a theoretical study of laser operation under two-color pump on the basis of the experimentally measured parameters of the specially prepared Er-doped tellurite fiber from TeO2-ZnO-La2O3-Na2O glass. It has been shown numerically that, for an optimal fiber length, the small-signal gain may exceed 18 dB and laser generation may be achieved with a relatively low threshold of a few hundreds of mW and a maximum slope efficiency can be ~40%. In addition, we have demonstrated in experiment a prototype of the power-scalable Er silica fiber source generating simultaneously near 1.56 and 1.7 µm, which may be used for implementing the proposed two-color pumped laser and amplifier.