We study the impact of Amplified Spontaneous Emission (ASE) noise on a Semiconductor Optical Amplifier (SOA)-based optical pulse delay discriminator and SOA-based distance ranger. Our experiments show that ASE reduces the sensitivity of these SOA-based devices and we confirm this finding by carrying out extensive simulations by modeling the ASE response of SOAs. The simulation results, obtained by numerical integration of these equations in MATLABTM using the NIMRODTM portal, are in qualitative agreement with experimental results.