  Amplification of bursts of ultrashort pulses is very challenging when the
intraburst repetition frequency reaches the THz range, corresponding to
(sub)-ps intervals between consecutive pulses. Periodic interference
significantly modifies conditions for chirped pulse amplification (CPA) which
gives rise to temporal and spectral distortions during CPA due to the optical
Kerr nonlinearity. Multi-pulse chirped amplification to mJ energies may lead to
a pronounced degradation of burst fidelity and the appearance of periodic
temporal satellites after de-chirping the amplified waveform. We study,
experimentally and numerically, the limitations of THz burst-mode CPA caused by
self- and cross-phase modulation. A number of practical recipes to suppress
nonlinear distortions and improve energy scaling by optimizing burst parameters
and applying modulation techniques are presented.
