We　report　on　the　experimental　realization　of　a　stable　high-power　all-fiber　broadband　amplified　spontaneous　emission　(ASE)　source　at　1992　nm　by　using　an　MOPA　configuration.　The　ASE　source　yields　a　maximum　output　power　of　25　W　with　a　slope　efficiency　of　49%,　and　the　wavelength　range　spanned　from　1930　to　2100　nm　with　a　full-width　at　half-maximum　bandwidth　of　25　nm.　In　addition,　we　also　measure　the　output　power　stability　of　the　high-power　broadband　ASE　source　and　a　narrowband　CW　fiber　laser　with　the　same　thulium-doped　fiber　main　amplifier　under　incident　pump　power　of　66　W.　The　output　power　fluctuation　of　the　high-power　broadband　ASE　source　is　below　+/-　0.3%,　which　is　much　lower　than　that　(+/-　2.3%)　of　narrowband　continuous　wave　thulium-doped　fiber　laser.