High-performance Mid-Infrared InP-based Quantum Cascade Lasers Monolithically Integrated Onto Silicon

A mid-infrared InP-based quantum cascade laser (QCL) structure is directly grown by molecular beam epitaxy on an 8-in. Ge-coated Si template. The semiconductor structure employs a metamorphic (GaAs/AlInAs) buffer and a strain-compensated active region comprising 26 stages based on an Al0.68In0.32As/Ga0.32In0.68As composition to achieve a record-high wall plug efficiency of 11% for a mid-infrared QCL-on-Si and a peak optical output power exceeding 10 W from a 10 mm × 30.3 μm ridge waveguide device. The device emission wavelength is centered at λ = 4.4 μm. Characterization by cathodoluminescence and transmission electron microscopy reveals a threading dislocation density of 1.0 × 107 cm−2 in the upper cladding and 3.7 × 107 cm−2 in the active region. These results present an advancement in the integration of high performance QCLs on silicon photonic platforms, further paving the way for scalable, low cost mid-infrared photonic integration.