  We demonstrate a new regime for mid-infrared optical parametric chirped pulse
amplification (OPCPA) based on achromatic quasi-phase-matching. Our
mid-infrared OPCPA system is based on collinear aperiodically poled lithium
niobate (APPLN) pre-amplifiers and a non-collinear PPLN power amplifier. The
idler output has a bandwidth of 800 nm centered at 3.4 $\mu$m. After
compression, we obtain a pulse duration of 44.2 fs and a pulse energy of 21.8
$\mu$J at a repetition rate of 50 kHz. We explain the wide applicability of the
non-collinear QPM amplification scheme we used, including how it can enable
octave-spanning OPCPA in a single device when combined with an aperiodic QPM
grating.
