Amorphous silicon optical waveguides and Bragg mirrors

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review


  • A. Khanna
  • M. Mulot
  • S. Arpiainen
  • A. Säynätjoki
  • J. Ahopelto
  • S. Honkanen
  • Harri Lipsanen

Research units

  • VTT Technical Research Centre of Finland


We study 200 nm thick hydrogenated amorphous silicon (a-Si:H) optical strip waveguides fabricated by Plasma Enhanced Chemical Vapor Deposition (PECVD) technique over PECVD silicon oxide on top of standard silicon wafer. The layer of a-Si:H is etched by Reactive Ion Etching (RIE). The ability to deposit a-Si:H at low temperatures (~250°C) by PECVD renders it a promising material for integration of optical waveguides with microelectronics. Waveguides with width varying from 2 μm to 10 μm exhibit low loss. Material refractive index data of a-Si:H is measured by reflectometry and is used in simulations. A high refractive index contrast between a-Si:H and air allows tight optical confinement of modes. We demonstrate Bragg gratings fabricated by e-beam writing technology on top of the waveguides. The period of the grating is approximately 300 nm and the depth of the grooves is about 30 nm. The grating on top of the waveguide act as mirror.


Original languageEnglish
Title of host publicationSilicon Photonics and Photonic Integrated Circuits
EditorsGC Righini, SK Honkanen, L Pavesi, L Vivien
Publication statusPublished - 2008
MoE publication typeA4 Article in a conference publication
EventSilicon Photonics and Photonic Integrated Circuits - Strasbourg, France
Duration: 7 Apr 200810 Apr 2008

Publication series

NameProceedings of SPIE
ISSN (Print)0277-786X


ConferenceSilicon Photonics and Photonic Integrated Circuits

    Research areas

  • Amorphous silicon, Bragg mirror, Propagation loss, Strip waveguide

ID: 5564408