The specification describes an optical fiber device for propagating and
recompressing high energy, ultrashort pulses with minimal distortions due
to nonlinearity. The device is based on propagation in a higher order
mode (HOM) of a few-moded fiber. Coupling into the HOM may be
accomplished using long-period gratings. Features of the HOM fiber mode
that are useful for high quality pulse compression include large
effective area, high dispersion and low dispersion slope. In a preferred
case the long period gratings go through a turn-around point (TAP) at the
wavelength of operation.