RESUMO
On-chip planer optical waveguide-based sources for supercontinuum (SC) generation have become highly attractive devices in the twenty-first century. Mid-IR SC sources in the 2-20 ?m wavelength region are advantageously used for gas sensing, high-sensitivity molecular detection, security, and industrial applications. These integrated photonic devices are cost-effective, scalable, and robust, and also offer more flexibility in tailoring the dispersion characteristics relative to other SC generation techniques. This article reviews the evolution of SC sources from fiber-based devices to optical waveguide-based devices and presents a historical as well as recent progress in various types of on-chip optical waveguides with physical mechanisms involved in generating coherent SC sources.