ABSTRACT
Semiconductor optical amplifier (SOA) can be classified based on the material used for the active region, where each material has advantages and disadvantages. In the traveling-wave (TW)-SOA, both facets are coated with an antireflective layer, and the optical signal travels only once through the active region. In order to analyze the SOA's performance, it is first necessary to identify the main physical processes underlying its operation, which are related to the interaction mechanisms between photons and carriers. Spontaneous recombination can usually be viewed as an undesirable side effect of SOA operation, from several viewpoints. Both TW- and R-SOA have found their application niches within the optical networks and photonic circuits. The system of equations describing SOA needs to be solved in a self-consistent manner due to the coupling between the signal and noise though the carrier rate equation.
