  We developed a predictive model describing harmonic generation and
intermodulation distortions in semiconductor optical amplifiers (SOAs). This
model takes into account the variations of the saturation parameters along the
propagation axis inside the SOA, and uses a rigorous expression of the gain
oscillations harmonics. We derived the spurious-free dynamic range (SFDR) of a
slow light delay line based on coherent population oscillation (CPO) effects,
in a frequency range covering radar applications (from 40kHz up to 30GHz), and
for a large range of injected currents. The influence of the high order
distortions in the input microwave spectrum is discussed, and in particular, an
interpretation of the SFDR improvement of a Mach-Zehnder modulator by CPOs
effects in a SOA is given.
