We present a systematic numerical design and performance study of an ultra-broadband noncollinear optical parametric chirped pulse amplification (NOPCPA) system. Using a split-step Fourier approach, we model a three-stage amplifier system which is designed for the generation of 7 fs pulses with multi-terawatt peak intensity. The numerical results are compared with recent experimental data. Several important aspects and design parameters specific to NOPCPA are identified, and the values of these parameters required to achieve optimal working conditions are investigated. We identify and analyze wavelength-dependent gain saturation effects, which are specific to NOPCPA and have a strong influence on the parametric amplification process. © Springer-Verlag 2007.