The Semiconductor optical amplifier (SOA) technology has a promising commercial value and viability in fiber optic communication systems. The SOA is usually employed as a booster or pre-amplifier in various optical communication networks. On the other hand, SOAs is also a strong option when operation as multi-functional elements in future all-optical networks is concerned. However with this in mind, the purpose of this project is to design a system employing SOAs as functional devices, for instance the noise reducer utilizing spectrum slicing source. The SOA is therefore modeled and simulated using the OptiSystem software. The SOA gain characteristic is also used to assist the design of the modeled SOA in order to prove a saturation gain case to reduce the Intensity noise. The performances of the systems are thus analyzed in terms of the Q-factor and bit-error-rate (BER) of the eye diagram, Relative intensity noise (RIN) and the optical signal-to-noise ratio (OSNR). The study of the SOA gain characteristics is in large agreement with the numerical simulation results by about 2.47%.The SOA presents a promising option when operating as a functional device in all optical communication