To　meet　the　application　requirements　of　photoelectric　countermeasures，hyperspectral　lidar，and　optical　coherence　tomography，among　others，nIR　supercontinuum　output　with　high　flatness　must　be　obtained　and　the　effect　the　backwardness　of　light　enhancement　on　the　stability　of　a　laser　system　during　non⁃　linear　amplification　should　be　prevented.　The　experiment　employed　a　picosecond　pulse　laser　seed　source　with　nonlinear　frequency　component，and　the　laser　was　built　with　a　fiber　nonlinear　amplifier　to　produce　su⁃　percontinuum　output　directly，solving　the　problem　of　returning　light　effectively.　Using　the　nonlinear　fiber　amplifier　to　generate　supercontinuum　is　an　effective　way　to　realize　a　high-power　supercontinuum　light　source.　The　method　combines　the　laser　gain　amplification　process　with　the　nonlinear　supercontinuum　broadening　process，achieving　simple　and　compact　system　structure.　The　SESAM　passive　mode-locked　picosecond　pulse　was　used　to　achieve　a　first-order　Stokes　frequency　broadening　through　two-stage　amplifi⁃　cation.　Finally，a　third-stage　nonlinear　fiber　amplifier　was　used　to　realize　a　near-infrared　supercontinuum　output　power　of　56　W　at　a　wavelength　range　of　950~1650　nm，flatness　of　10　dB（excluding　pump　light），and　opto-optical　conversion　efficiency　of　48%.　©　2022　Chinese　Academy　of　Sciences.　All　rights　reserved.