This article is a simplified analysis of a convenient thulium fiber laser source with 3 W of output power operating at a wavelength of 2059 nm with a slope efficiency of 49% with respect to input pump power and 60% with respect to absorbed pump power. The laser was applied in an atomic helium spectroscopy experiment to quench ³He (2058.63 nm) and ⁴He (2058.69 nm) meta-stable singlets (2¹S0), allowing for further investigation of the helium fine structure.