Recent advances in ultrafast laser technology have led to the generation of
light pulses comprising few optical cycles employing different compression
techniques. In particular, two techniques have been developed, which allow
addressing the issues of high peak power or frequency tunability in a wide
spectral range, namely: the hollow-fiber compression technique and the opt
ical parametric amplification. This paper analyzes the general scheme of pu
lse compression and reports on the most interesting results obtained using
the above-mentioned techniques. The combination of spectral broadening in a
gas-filled hollow fiber with ultrabroad-band dispersion control, has led t
o the generation of pulses with duration of similar to5 fs with peak powers
up to 0.11 TW. Using optical parametric amplifiers with different configur
ations sub-15-fs laser pulses have been generated tunable in the visible an
d in the near-infrared.