We report on an ytterbium-free, erbium-doped single-mode all-fiber laser reaching a record output power of 107 W at 1598 nm, with slope efficiency 38.6% according to the absorbed pump 981 nm. The gain fiber, co-doped cerium, aluminum, and phosphorus, was fabricated in-house adjusted doping concentrations reduce erbium ions clustering, thereby increasing while keeping numerical aperture low ensu...