Widely tunable integrated GaAs and AlGaAs platforms for efficient second-order frequency conversion

Integrated coherent sources in the mid-infrared (mid-IR) are essential for spectroscopy and quantum frequency conversion (QFC) of single photons to enable their use in fiber-based applications. Direct emission in the mid-IR is limited and requires complex fabrication and large power consumption. Here, a mid-IR laser is demonstrated with a continuous tuning range of >80 nm centered around 2360 nm, through difference-frequency generation (DFG). The nonlinear coefficient d₁₄ of gallium arsenide (GaAs) and aluminum gallium arsenide (AlGaAs) on insulator is measured for the first time using second-harmonic generation (SHG) in waveguides with various lengths. These platforms are discussed to obtain a high conversion efficiency for tunable single photon emitters using monolithic epitaxial quantum dots and integrated waveguides for QFC.