Mid-infrared difference-frequency generation in AlGaAs-on-insulator waveguides

Abstract

A design study is presented for difference-frequency generation (DFG) to the mid-infrared (MIR) at 2.3 µm in AlGaAs waveguides heterogeneously integrated on silicon. Perfect phase matching (PhM) is achieved in simulations by engineering the dimensions of the waveguide and by tuning the wavelengths of the input sources. An optimal design of the waveguide is found with a width of 1196 nm and height of 146 nm with a length of about 5 mm. We expect a signal output power of about 1 mW at 2389 nm and a wavelength range from 2231 to 2574 nm by the use of tunable sources around 940 and 1550 nm. The tolerance of the input wavelengths and waveguide dimensions required for perfect PhM is also estimated showing the feasibility of the fabrication. This offers a promising design for a compact MIR source on a chip to be used for gas sensing, in particular for carbon monoxide and ammonia, and for DFG of single photons to the C-band.