An all-fiber optical pulse cleaner (OPC) is investigated based on nonlinear polarization rotation (NPR). The theoretical analysis of pulse contrast enhancement using NPR is detailed. The relation of transmittivity versus incident angle and fiber length is calculated. The change of pulse width and shape of the output pulse is investigated. And an OPC operating at 1053 nm with a hundred picoseconds pulse duration is demonstrated. The pulse contrast between main pulse and continuous wave background power is enhanced by more than 47.5 dB,and the contrast ratio between main pulse and prepulses is enhanced by more than 16.94 dB,which are both beyond the response limit of the detecting devises. The overall peak power transmittivity of the system is 28.05%,and the duration of the pulse is shortened from 92 to 64 ps,which is in agreement with the theoretical prediction. Efficiency measurements are realized using an optical-to-electrical converter and an attenuator,for the autocorrelator is not applicable to the measurement of the pulses with 1 Hz repetition rate . More enhancement of contrast ratio will be detected with precise detection.