Abstract: The influences of the pulse duration, chirp， and initial spectrum of the femtosecond laser on the supercontinuum generated in fused silica have been investigated theoretically. Results show that, with the increase of the pulse duration, the cut-off wavelength of the blue-extension becomes longer and the spectral intensity becomes lower at the constant energy. For the laser with pulse duration larger than 150 fs, the spectral intensity of the blue-extension generated by the negatively chirped pulse is higher than those generated by the freely-chirped pulse and the positively chirped pulse.

Key words: pulse duration, fused silica, chirped pulse, supercontinuum