“…The advantage of the MMI as compared to the directional coupler, which can perform analog functions, lies in its robustness toward processing and in its less polarization dependent behavior. This device has also been fabricated in a semiconductor optical amplifier (SOA)-based layer structure in several applications, e.g., high-power lasers [3], regenerators [4], [5], and wavelength converters [6]. However, some side effects, namely lateral carrier diffusion and surface recombination, which result from the active layout, should not be neglected in the design of SOA-based MMIs.…”