Continuous-wave oscillation of Tm³⁺-doped fluorozirconate fibre lasers at around 1.47µm, 1.9µm and 2.3µm when pumped at 790nm

Continuous operation of Tm3+-doped fluorozirconate fibre lasers at around 1.47m, 1.9µm and 2.3µm has been demonstrated when pumping at around 790nm with a Ti:sapphire laser. The efficiency of the 1.9 µm 3H4 - 3H6, transition was found to be significantly increased by enforcing simultaneous oscillation on the 3F4 - 3H5 transition at 2.3µm as this effectively enhances the branching ratio for pumping the 3H4 level. An upconversion process leading to blue emission has also been observed. The efficiency of this process is enhanced by more than an order of magnitude as soon as laser oscillation takes place at 2.3 µm, indicating the potential application of manipulating branching ratios via lasing