Modulational instability in a silicon-on-insulator directional coupler: role of the coupling-induced group velocity dispersion

Wei Ding, Owain K Staines, Gareth D Hobbs, Andriy V Gorbach, Charles De Nobriga, William J Wadsworth, Jonathan C Knight, Dmitry V Skryabin, Michael Strain, M. Sorel

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9 Citations (Scopus)


We report frequency conversion experiments in silicon-on-insulator (SOI) directional couplers. We demonstrate that the evanescent coupling between two subwavelength SOI waveguides is strongly dispersive and significantly modifies modulational instability (MI) spectra through the coupling induced group velocity dispersion (GVD). As the separation between two 380-nm-wide silicon photonic wires decreases, the increasing dispersion of the coupling makes the GVD in the symmetric supermode more normal and suppresses the bandwidth of the MI gain observed for larger separations.
Original languageEnglish
Pages (from-to)668-670
Number of pages3
JournalOptics Letters
Issue number4
Publication statusPublished - 15 Feb 2012


  • frequency conversion experiments
  • silicon-on-insulator directional couplers
  • group velocity dispersion
  • bandwidth

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