We demonstrate a self-starting erbium fiber oscillator-amplifier system based on the nonlinear polarization rotation mode-locked mechanism.The direct output pulse from the amplifier is 47fs with an average power of 1.22 W and a repetition rate of 50 MHz,corresponding to a pulse energy of 24 nJ.The full width at half-maximum of the spectrum of the output pulses is approximately 93nm at a central wavelength of 1572nm so that the transformlimited pulse duration is as short as 39 fs.Due to the imperfect dispersion compensation,we compress the pulses to 47fs in this experiment.