  We experimentally demonstrate the generation of a temporal pulse doublet from
the propagation of an initial super-Gaussian waveform in a nonlinear focusing
medium. The picosecond structures are characterized both in amplitude and phase
and their close-to-Gaussian Fourier-transform limited shape is found in
excellent agreement with numerical simulations. This nonlinear fiber-based
single-stage reshaping scheme is energy efficient, can sustain GHz repetition
rates and temporal compression factors around 10 are demonstrated.
