Energy-efficient semiconductor optical amplifier with longitudinally varying confinement factor

A novel, to the best of our knowledge, type of semiconductor optical amplifier (SOA) with improved energy efficiency is presented conceptually and simulated numerically, using parameters based on a well-established heterogeneous photonic integration platform. The SOA has a confinement factor that can be varied by a waveguide design only, and thus the gain, loss, and saturation can be tailored along the light propagation direction. By using a tapered waveguide, the SOA can be designed for high gain at the input and high saturation at the output. By optimizing the design, it is shown that an almost 2-dB increase in saturation input power and a 10% increase in efficiency can be achieved, as compared to existing designs. This SOA design can be a key enabler for generic heterogeneous photonic integration platforms.