  Dispersion management of few-cycle pulses is crucial for ultrafast optics and
photonics. Often, nontrivial dispersion is compensated using complex optical
systems or minimized through careful design of waveguides. Here, we present
dispersion-managed adiabatic frequency conversion enabling efficient
downconversion of an 11.1-fs near-IR pulse to an 11.6-fs mid-IR pulse spanning
an octave of bandwidth from 2-4 $\mu$m. The adiabatic frequency converter is
designed to impart a constant group delay over the entire bandwidth,
eliminating the need for complex dispersion management and opening a new avenue
for dispersion engineering in ultrafast optics and photonics. Notably,
dispersion engineering through the position-dependent conversion position of an
adiabatic conversion device constitutes an additional mechanism for dispersion
control in ultrafast optics and photonics while maintaining high conversion
efficiency for broadband pulses.
