Highly coherent on-chip mid-infrared supercontinuum generation from 1.5 to 25 μm in CdTe-based Rib waveguide

Abstract

We present design and computational analysis of a rib waveguide composed of a core of CdTe chalcogenide glass having upper and lower cladding of Zinc Selenide (ZnSe) for high coherence on-chip supercontinuum (SC) generation. CdTe chalcogenide glass, known for its wide transparency range extending from visible to mid-infrared region, is utilized in our design to achieve broad spectral coverage. Additionally, its higher non-linear refractive index enhances the supercontinuum generation efficiency. Using Finite Element Method (FEM), we conducted the dispersion engineering by analyzing the influence of waveguide geometrical parameters. This optimization is aimed at minimizing the dispersion values and to obtain a flat top dispersion profile. The proposed design offers a Zero Dispersion Wavelength (ZDW) approximately near 2.6 μm. Our simulation reports a supercontinuum spectrum broadening covering 1.5–25 μm, when pumped with 2.5 μm secant hyperbolic pulses having pulse width 50 fs and peak power 16 kW in only 1 mm length of waveguide. The high coherence of the final generated spectra positions our proposed design as a promising candidate for various non-linear applications including non-linear microscopy, optical coherence tomography, frequency comb generation and non-linear spectroscopy.