  A Martinez-type stretcher-compressor is used to modify the spectral phases of
a high-power (~1 W) QCL comb emitted at 8.2 {\mu}m with more than 100 cm-1
spectral bandwidth. Using this scheme, we demonstrate a compression of the QCL
output from a 134 ps continuous wave waveform, to a train of pulses of width 12
ps, and a power with peak to average ratio of 40.7. An evaluation of the phase
noise of the free-running device yields an integrated timing jitter of 335 fs
over the frequency range 20 kHz - 100 MHz, and a pulse-to-pulse jitter of 2.0
fs.
