title: Air-clad silicon pedestal structures for broadband mid-infrared microphotonics.
abstract: Toward mid-infrared (mid-IR) silicon microphotonic circuits, we demonstrate broadband on-chip silicon structures, such as: (i) straight and bent waveguides and (ii) beam splitters, utilizing an air-clad pedestal configuration which eliminates the need for typical mid-IR-lossy oxide cladding. We illustrate a sophisticated fabrication process that can create high-quality pedestal structures in crystalline silicon, while preserving its mid-IR transparency. A fundamental waveguide mode is observed between λ=2.5 μm and λ=3.7 μm, and an optical loss of 2.7 dB/cm is obtained at λ=3.7 μm. Our pedestal silicon structures show 50:50 mid-IR power splitting enabling the further development of mid-IR silicon microphotonics.
authors.affiliation: Materials Processing Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. paolin@mit.edu
authors.forename: Pao Tai
authors.initials: PT
authors.lastname: Lin
authors.forename: Vivek
authors.initials: V
authors.lastname: Singh
authors.forename: Yan
authors.initials: Y
authors.lastname: Cai
authors.forename: Lionel C
authors.initials: LC
authors.lastname: Kimerling
authors.forename: Anu
authors.initials: A
authors.lastname: Agarwal