Numerical Rate Equation Modeling of a ${\sim {\hbox {2.1}}-}\mu{\hbox {m}}-{\rm Tm}^{3+}/{\rm Ho}^{3+}$ Co-Doped Tellurite Fiber Laser

Judd–Ofelt analysis is performed on measurements of bulk samples of ${\rm Tm}^{3+}$ - and ${\rm Ho}^{3+}$ -doped tellurite glass from which the host-dependent Judd–Ofelt intensity parameters are extracted. These have then been used to calculate the radiative rates and branching ratios in this particular material system. A rate-equation approach is then used to model an experimentally realized ${\sim {\hbox {2.1}}}\,\mu{\hbox {m}}\,{\rm Tm}^{3+}/{\rm Ho}^{3+}$ codoped tellurite fiber laser and extract values of the energy transfer and upconversion rate parameters in ${\rm TeO}_{2}-{\rm ZnO}-{\rm Na}_{2}{\rm O}$ (TZN) glass. Excellent agreement is found between simulated and experimental data, which indicates the validity of the approach.