On-Chip Mid-Infrared Supercontinuum Generation from 3 to 13 μm Wavelength
Miguel Montesinos‐Ballester, Christian Lafforgue, Jacopo Frigerio, Andrea Ballabio, Vladyslav Vakarin, Qiankun Liu, Joan Manel Ramírez, Xavier Le Roux, David Bouville, Andrea Barzaghi, Carlos Alonso‐Ramos, Laurent Vivien, Giovanni Isella, Delphine Marris‐Morini
Abstract
High Resolution Image Download MS PowerPoint Slide Midinfrared spectroscopy is a universal way to identify chemical and biological substances. Indeed, when interacting with a light beam, most molecules are responsible for absorption at specific wavelengths in the mid-IR spectrum, allowing to detect and quantify small traces of substances. On-chip broadband light sources in the mid-infrared are thus of significant interest for compact sensing devices. In that regard, supercontinuum generation offers a mean to efficiently perform coherent light conversion over an ultrawide spectral range, in a single and compact device. This work reports the experimental demonstration of on-chip two-octave supercontinuum generation in the mid-infrared wavelength, ranging from 3 to 13 μm (that is larger than 2500 cm –1 ) and covering almost the full transparency window of germanium. Such an ultrawide spectrum is achieved thanks to the unique features of Ge-rich graded SiGe waveguides, which allow second-order dispersion tailoring and low propagation losses over a wide wavelength range. The influence of the pump wavelength and power on the supercontinuum spectra has been studied. A good agreement between the numerical simulations and the experimental results is reported. Furthermore, a very high coherence is predicted in the entire spectrum. These results pave the way for wideband, coherent, and compact mid-infrared light sources by using a single device and compatible with large-scale fabrication processes.