Summary form only given. Presents a comparison between different pumping schemes implemented within fluoride doped fibers. The first part deals with the performances of different up-conversion pumps. In the second part, the advantages and drawbacks of several ground state pump wavelengths are discussed. The dual-wavelength-pumping schemes have led to huge efficiency improvement (up to 50%), with regard to noise performances and the band location for WDM systems. These results make the thulium-doped fiber amplifier (TDFA) one of the most serious amplifying devices for future WDM systems.