Effects of first-order nonlinearity and dispersion on super-Gaussian pulse propagation in single-mode optical fibers are numerically investigated.The results show that super-Gaussian oscillations caused by positive higher-order dispersion3βcome forth near the peak and trailing of the back edge of the pulse

while those caused by the negative3βappear near the peak and trailing of the front edge of the pulse.The greater the shape parametermof the pulse edge

the greater the peak value of the super-Gaussian pulse caused by the first-order nonlinearity and the second-order dispersion at the initial phase of the propaga-tion

and the narrower the pulse width and

at the same time

the longer the propagation distance

the smaller the peak value

the wider the pulse width and the greater the chirp

while the smaller them

the better the linearity of the chirps over a fairly large region around the center of the pulse.