A fiber laser system emitting high-quality ultrashort powerful light pulses is reported. The photonic crystal fiber featuring high-gain large -mode-core and short absorption length is used, and the fiber laser is passively mode-locked by a semiconductor saturable absorber mirror. Its output greatly exceeds the power limitation of single-mode fiber oscillators with 1.4-W average power at 1 039-nm center wavelength, 6.9-ps pulse width, and 45.4-MHz repetition rate.