Mid-IR laser sources monolithically integrated on Si substrates

The integration of mid-IR lasers with Si-based platforms is needed for the development of smart sensor grids. Here we review our recent results on GaSb-based laser diodes (LDs) and InAs/AlSb quantum-cascade lasers (QCLs), grown on on-axis (001) Si substrates by molecular-beam epitaxy, and covering emission wavelengths from 2 to 10 µm. Threshold current densities well below 1 kA.cm-2 are achieved in both cases. Ridge LDs operate cw up to 80 °C and emit around 10 mW at room temperature whereas QCLs exhibit performances comparable to their counterpart grown on native InAs substrates. In addition, we will demonstrate that etching facets is a viable route toward cavity definition.