title: An octave-spanning mid-infrared frequency comb generated in a silicon nanophotonic wire waveguide.
abstract: Laser frequency combs, sources with a spectrum consisting of hundred thousands evenly spaced narrow lines, have an exhilarating potential for new approaches to molecular spectroscopy and sensing in the mid-infrared region. The generation of such broadband coherent sources is presently under active exploration. Technical challenges have slowed down such developments. Identifying a versatile highly nonlinear medium for significantly broadening a mid-infrared comb spectrum remains challenging. Here we take a different approach to spectral broadening of mid-infrared frequency combs and investigate CMOS-compatible highly nonlinear dispersion-engineered silicon nanophotonic waveguides on a silicon-on-insulator chip. We record octave-spanning (1,500-3,300 nm) spectra with a coupled input pulse energy as low as 16 pJ. We demonstrate phase-coherent comb spectra broadened on a room-temperature-operating CMOS-compatible chip.
authors.affiliation: 1] Photonics Research Group, Department of Information Technology, Ghent University-imec, Sint-Pietersnieuwstraat 41, 9000 Ghent, Belgium [2] Center for Nano- and Biophotonics (NB-Photonics), Ghent University, 9000 Ghent, Belgium.
authors.forename: Bart
authors.initials: B
authors.lastname: Kuyken
authors.affiliation: Max Planck Institut für Quantenoptik, Hans-Kopfermannstrasse 1, 85748 Garching, Germany.
authors.forename: Takuro
authors.initials: T
authors.lastname: Ideguchi
authors.affiliation: 1] Max Planck Institut für Quantenoptik, Hans-Kopfermannstrasse 1, 85748 Garching, Germany [2] Ludwig-Maximilians-Universität München, Fakultät für Physik, Schellingstrasse 4/III, 80799 Munich, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Holzner
authors.affiliation: 1] Max Planck Institut für Quantenoptik, Hans-Kopfermannstrasse 1, 85748 Garching, Germany [2] Ludwig-Maximilians-Universität München, Fakultät für Physik, Schellingstrasse 4/III, 80799 Munich, Germany.
authors.forename: Ming
authors.initials: M
authors.lastname: Yan
authors.affiliation: 1] Max Planck Institut für Quantenoptik, Hans-Kopfermannstrasse 1, 85748 Garching, Germany [2] Ludwig-Maximilians-Universität München, Fakultät für Physik, Schellingstrasse 4/III, 80799 Munich, Germany.
authors.forename: Theodor W
authors.initials: TW
authors.lastname: Hänsch
authors.affiliation: imec, Kapeldreef 75, 3001 Leuven, Belgium.
authors.forename: Joris
authors.initials: J
authors.lastname: Van Campenhout
authors.affiliation: imec, Kapeldreef 75, 3001 Leuven, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Verheyen
authors.affiliation: Department of Physics, The University of Auckland, Private Bag 92019 Auckland, New Zealand.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Coen
authors.affiliation: 1] Photonics Research Group, Department of Information Technology, Ghent University-imec, Sint-Pietersnieuwstraat 41, 9000 Ghent, Belgium [2] Center for Nano- and Biophotonics (NB-Photonics), Ghent University, 9000 Ghent, Belgium.
authors.forename: Francois
authors.initials: F
authors.lastname: Leo
authors.affiliation: 1] Photonics Research Group, Department of Information Technology, Ghent University-imec, Sint-Pietersnieuwstraat 41, 9000 Ghent, Belgium [2] Center for Nano- and Biophotonics (NB-Photonics), Ghent University, 9000 Ghent, Belgium.
authors.forename: Roel
authors.initials: R
authors.lastname: Baets
authors.affiliation: 1] Photonics Research Group, Department of Information Technology, Ghent University-imec, Sint-Pietersnieuwstraat 41, 9000 Ghent, Belgium [2] Center for Nano- and Biophotonics (NB-Photonics), Ghent University, 9000 Ghent, Belgium.
authors.forename: Gunther
authors.initials: G
authors.lastname: Roelkens
authors.affiliation: 1] Max Planck Institut für Quantenoptik, Hans-Kopfermannstrasse 1, 85748 Garching, Germany [2] Ludwig-Maximilians-Universität München, Fakultät für Physik, Schellingstrasse 4/III, 80799 Munich, Germany [3] Institut des Sciences Moléculaires d'Orsay, CNRS, Bâtiment 350, 91405 Orsay, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Picqué