Chirped and tapered Quantum Dot semiconductor optical amplifiers (SOAs) are a valid solution for the direct amplification of ultra-short pulsed sources such as mode-locked lasers, thanks to their broad gain bandwidth and fast recovery times. Traditionally, the SOAs are operated in a so-called single-pass configuration: the radiation enters from one facet, it is amplified and exits from the opposite side. However, it was found out in literature that a double-pass configuration, where the radiation is extracted from the same facet it is injected into, can lead to enhanced performances, increasing gain and output power, with a limited degradation of the amplified pulses duration, making this configuration a possible future standard for the amplification of light sources.