Widely tunable mid-infrared generation via frequency conversion in semiconductor waveguides

Phase matching in a multilayer AlGaAs waveguide is used to generate mid-IR (7.5-8.5 μm) light through difference frequency generation (DFG) between a 1550 nm pump and 1950 nm signal. This represents the longest wavelength generated through DFG in a 2D waveguide mode in a semiconductor waveguide. It was produced with an efficiency of 1.2×10(-4) %/W in a 1 mm long sample. The process is shown to be tunable across >2 μm through appropriate tuning of the input pump and signal wavelengths and/or waveguide geometry, and is therefore a viable platform for monolithic, tunable, mid-IR sources.