The semiconductor optical amplifiers (SOA) are becoming key elements of modern communication systems, particularly in view of optical signal processing. The carrier dynamics in the gain medium can be exploited to implement all-optical wavelength conversion, demultiplexing, clock recovery and signal regeneration. It can be integrated with waveguides to form compact and polarization-insensitive functional devices. A very compact Michelson interferometer, obtained by monolithic integration of two SOA with a passive waveguide section, incorporating turning mirrors is presented. Basing on the cross-phase modulation effect, taking place in the SOA under optical pumping, a device developed and used to obtain wavelength conversion
