The ultrashort pulse source with supercontinuum up to 40～60 nm at a repetition rate of 2.5 GHz was obtained by a variety of nonlinear effects in the optical fiber. The ultrashort pulses with pulsewidth of 5.7 ps and 3.6 ps were filtered from supercontinuum source at different wavelength by applying two optical filters with bandwidth of 0.4 nm and 1.2 nm, respectively. It was demonstrated by experiments that the four-wave mixing influenced the generation of supercontinuum greatly.