Compact integrated interferometer with semiconductor optical amplifiers

Semiconductor optical amplifiers (SOAs) 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. Furthermore, SOAs can be integrated with waveguides to form compact and polarization-insensitive functional devices. In this contribution we present a very compact Michelson interferometer, obtained by monolithic integration of two SOAs with a passive waveguide section, incorporating turning mirrors. It operates in the 1550 nm window. Based on the cross-phase modulation effect, taking place in the SOAs under optical pumping, we used our device to obtain wavelength conversion to wavelengths either longer or shorter than the pump wavelength.