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.