title: Modulational instability in a silicon-on-insulator directional coupler: role of the coupling-induced group velocity dispersion.
abstract: 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.
authors.affiliation: Centre for Photonics and Photonic Materials, Department of Physics, University of Bath, Bath, UK. wding@iphy.ac.cn
authors.forename: W
authors.initials: W
authors.lastname: Ding
authors.forename: O K
authors.initials: OK
authors.lastname: Staines
authors.forename: G D
authors.initials: GD
authors.lastname: Hobbs
authors.forename: A V
authors.initials: AV
authors.lastname: Gorbach
authors.forename: C
authors.initials: C
authors.lastname: de Nobriga
authors.forename: W J
authors.initials: WJ
authors.lastname: Wadsworth
authors.forename: J C
authors.initials: JC
authors.lastname: Knight
authors.forename: D V
authors.initials: DV
authors.lastname: Skryabin
authors.forename: M J
authors.initials: MJ
authors.lastname: Strain
authors.forename: M
authors.initials: M
authors.lastname: Sorel
authors.forename: R M
authors.initials: RM
authors.lastname: De La Rue