47-W 1726-nm operation of a thulium fiber laser pumped in-band by an erbium-only fiber laser (Conference Presentation)

A route to high power continuous-wave generation around 1.7 µm has been explored using an Er-only doped LMA fiber laser for high brightness core pumping of a thulium-doped fiber laser (TDFL). The maximum output power of 47 W with a slope efficiency of 80% was achieved at 1726 nm which, to the author’s best knowledge, is the highest recorded power in this wavelength region from a TDFL. The motivation for an Er-only pump source is scalability; these results show that this configuration has significant potential for further power scaling towards hundred-watt class systems at 1.7 µm and beyond.