Analysis and design of dispersion-engineered cascaded channel waveguide for mid-infrared supercontinuum generation employing pump source at telecommunication wavelength

We theoretically investigate and propose a promising 8-mm-long cascade planar waveguide made of Si3N4 and As2Se3 glass system for mid-infrared supercontinuum generation by employing a commercially available femtosecond pump source operating at 1550 nm wavelength. A rigorous numerical investigation has been performed considering three different dispersion regions of the optimized cascade waveguide for expanding the SC coverage far into the mid-infrared. Based on the tailored dispersion region whether the anomalous or normal, the pump pulse is applied at the input of the initial waveguide segment of Si3N4 and the output of which is then coupled into the final waveguide segment made of As2Se3 glass system. The output supercontinuum spectrum for all-anomalous dispersion region expanded up to 10 mu m by one of the best reported so far using cascade design with coherency of unity over the entire spectrum region predicted. This would be the widest spectral coverage expanded into the mid-infrared, to the best of the authors' knowledge, by the cascade planar waveguide design employing a commercially available pump source in telecommunication window with a peak power of 5 kW. Such a highly coherent cascade planar waveguide, designed and proposed based on the concatenating principle for a broadband mid-infrared supercontinuum generation using the twostep process, would be highly suitable for many mid-infrared based applications such as sensing and biological imaging.

Automated summary

This study proposes a promising cascade planar waveguide design made of Si3N4 and As2Se3 glass system for mid-infrared supercontinuum generation using a commercially available femtosecond pump source. The design allows for expanding the supercontinuum coverage far into the mid-infrared region, making it suitable for applications like sensing and biological imaging.