Design of an ultra-compact As2Se3 waveguide for enhanced optical frequency comb generation

This study introduces a waveguide design capable of generating supercontinuum spectrum and frequency combs within the mid-infrared range. The proposed structure consists of an As2Se3 core and cladding layers of MgF2 and SiO2, exhibiting two zero-dispersion wavelengths at 2100 nm and 2850 nm. Theoretical modeling and numerical simulations demonstrate the generation of a supercontinuum spanning a wavelength range of 4500 nm, from 1000 to 5500 nm, at a − 30 dB level, as well as frequency combs featuring up to 44 comb lines with a flatness of 15 dBm. The supercontinuum was generated in the maximum range of 30 dB using a 1 kW input pulse and 1 and 4 mm long waveguides. The generated frequency combs cover the wavelength range of 2073.1–2159.8 nm, making them suitable for applications such as gas sensing, industrial process monitoring, and medical diagnostics. The proposed waveguide design offers advantages over existing methods in terms of the number of comb lines, flatness, and effective area while operating in the mid-infrared region.