Design and investigation of low polarization strained-barrier quantum well SOA co-integrated with passive waveguides

We propose a novel layerstack for polarization-insensitive (PI) multi quantum well (MQW) semiconductor optical amplifiers (SOAs) using a ternary InGaAs/InGaAs active layer with a tensile-strained barrier. This design achieves PI performance by enhancing TM-mode gain and is compatible with passive waveguides for passive-active co-integration. The SOA exhibits a high gain of 30 dB, broadband operation of 100 nm, and low polarization-dependent gain (PDG), ranging from 1-3.5 dB (in the full C-band). By widening the waveguide width from 1 μm to 3 μm, the output saturation power increases from 6 dBm to 12 dBm. Finally, we present the fabrication tolerance of SOAs.