  Ultrashort laser pulses that last only a few optical cycles have been
transformative tools for studying and manipulating light--matter interactions.
Few-cycle pulses are typically produced from high-peak-power lasers, either
directly from a laser oscillator, or through nonlinear effects in bulk or fiber
materials. Now, an opportunity exists to explore the few-cycle regime with the
emergence of fully integrated nonlinear photonics. Here, we experimentally and
numerically demonstrate how lithographically patterned waveguides can be used
to generate few-cycle laser pulses from an input seed pulse. Moreover, our work
explores a design principle in which lithographically varying the
group-velocity dispersion in a waveguide enables the creation of highly
constant-intensity supercontinuum spectra across an octave of bandwidth. An
integrated source of few-cycle pulses could broaden the range of applications
for ultrafast light sources, including supporting new lab-on-a-chip systems in
a scalable form factor.
