Optimization of mid-infrared dispersive wave generation at 3 µm in LiNbO3 waveguides

We propose an effective scheme to enhance mid-infrared dispersive wave (DW) emission, which includes dispersion engineering of the waveguide and the assistance of a CW trigger. Our suggested approach can help achieve better coherence and higher signal-to-noise ratio by adding a weak CW trigger with the femtosecond pulse pump in dispersion engineered lithium niobate (LiNbO 3 ) waveguides. First, the integrated dispersion profile of LiNbO 3 waveguides is designed based on dispersion engineering regarding the sidewall angle and slab thickness. Second, with the assistance of a weak CW trigger, the mid-infrared DW is enabled or further enhanced. The optimal CW-triggered wavelength and operating conditions are ascertained. Mid-infrared emission at around 3 µm with a sufficient power level is accessible after optimization, which is feasible for multi-species greenhouse gas detection through gas absorption spectroscopy.