Development of multi-step processing in silicon-on-insulator for optical waveguide applications

Kimmo Solehmainen (Corresponding Author), Timo Aalto, James Dekker, Markku Kapulainen, Mikko Harjanne, Päivi Heimala

Research output: Contribution to journalArticleScientificpeer-review

45 Citations (Scopus)


Multi-step processing for a silicon-on-insulator (SOI) platform was developed. It allows the incorporation of additional grooves and steps into the basic optical waveguide structures, so that light can be adiabatically coupled between waveguides with different cross-sections. The processes were based on simple fabrication methods easily scalable for mass production. Two options for the fabrication sequence were tested, both having one silicon etch step with an oxide mask and another etch step with a resist mask. The applicability of the developed processes was tested with different waveguide structures. An additional groove etched beside a bent 10 µm thick rib waveguide suppressed the bend losses to below 1 dB/90° with a 5 mm bending radius. A waveguide mirror exhibited optical losses below 1 dB/90°. The excess losses of a vertical taper between 10 and 4 µm thick rib waveguides were 0.7 dB. A converter between a rib and a strip waveguide showed negligible losses, below 0.07 dB.
Original languageEnglish
Pages (from-to)S455-S460
Number of pages16
JournalJournal of Optics A: Pure and Applied Optics
Issue number7
Publication statusPublished - 2006
MoE publication typeA1 Journal article-refereed


  • integrated optics
  • optical device fabrication
  • fabrication
  • optical losses
  • optical waveguides
  • silicon-on-insulator
  • SOI


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