High-power "Watt-level" CW operation of diode-pumped 27 �m fiber lasers using efficient cross-relaxation and energy transfer mechanisms

Abstract

We report the demonstration of high power (660 mW) CW operation of a diode-pumped mid-IR Er fiber laser. This was achieved by using efficient depopulation of the lower laser level via enhanced cross-relaxation between Er ions and energy transfer to Pr ions (at doping densities much higher than those used previously in Er:ZBLAN), along with optimal pumping of such lasers via custom-designed double-clad fluoride fibers.

High-Power ZBLAN Glass Fiber Lasers: Review and Prospect

“…So far, energytransfer process between Er 3+ ions and codoped Pr 3+ ions and energy-transfer upconversion process between Er 3+ and Er 3+ ions have been proven most efficient to depopulate the lower laser level 4 I 13/2 and solve the population bottleneck even with low-brightness pumping. Watt-level and 10-watt-level 2.7 μm lasers have been demonstrated in highconcentration singly Er-doped (>1 mol%) ZBLAN doubleclad fibers [14,16,78,87,88,90,91] and Er/Pr codoped ZBLAN double-clad fibers [76,77,89,90]. It should be noted that, the output of the first 10-watt-level 2.7 μm laser [14] was only constrained by the thermo-optic effects at high-power operation.…”

Effect of B2O3 addition on the thermal properties and density of barium phosphate glasses

“…For instance, there are reports on heavy-metal oxide glasses for IR transmitting materials [1], high refractive-index glasses for nonlinear optics [2], low-phonon-energy oxide, fluoride and chalcogenide glasses for optical fiber amplifiers in the telecommunication of broadband WDM [3], 1.46 lm [3], 1.3 lm [4] and for mid infrared (2-5 lm) fiber lasers [5,6].…”

Effect of TeO2 addition on thermal stabilities and 2.7 μm emission properties of fluoroaluminate–tellurite glass

“…On the one hand, among various rare earth ions, Er 3+ is an important rare earth ion to provide 2.7µmemission because of the 4 I 11/2 → 4 I 13/2 transition, and several results have been reported around 2.7µm emission in different kindsof Er 3+ doped crystals and glasses [2][3]. On the other hand, ZrF 4 -based fluoride glass possesses greatadvantages of high solubility for rare earth ions,low nonlinearrefractive indexas well as long fluorescencelifetime of the excited electronic states [4,[5][6].…”