The wavelength conversion of 1 GHz, 11 ps ultrashort optical pulses based on cross-gain modulation of a semiconductor optical amplifier is reported. The phenomena of the experiment are analyzed. The following experimental results are obtained: (1 ) The converted signal is obviously broadened, the full width at half-maximum (FWHM) of the converted signal is 20 times that of the initial signal laser; (2) The spectrum of the converted signal is compressedj (3) The central wavelength of the converted signal is redshifted ; (4) The extinction ratio of the converted signal is decreased.