The effect of temperature dependence of thulium cross sections on thulium-doped fiber laser operation

We report on the first measurement of the temperature dependent silica thulium-doped fiber absorption and emission cross-sections in the spectral range 700–2200 nm for a temperature range −196–300 °C. Using this data, we simulated the effect of temperature-induced shift of cross-sections on high power thulium-doped fiber laser (TDFL) performance when clad-pumped at 790 nm. The simulations show considerable impact on TDFL threshold and efficiency for shorter fiber length. The effect is most apparent for amplifier setup, especially with strong amplified spontaneous emission.