title: Gap solitons on a ring.
abstract: We introduce a new species of gap solitons (GSs) supported by an azimuthally modulated guiding ring in defocusing cubic media. The periodicity in the azimuthal direction strongly modifies properties and existence domains of GSs. In addition to the fundamental solitons, we report even and twisted bound states. The former type is found to be stable, while the twisted states are always unstable in defocusing media.
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, Universitat Politecnica de Catalunya, Mediterranean Technology Park, Castelldefels (Barcelona), Spain. Yaroslav.Kartashov@icfo.es
authors.forename: Yaroslav V
authors.initials: YV
authors.lastname: Kartashov
authors.forename: Boris A
authors.initials: BA
authors.lastname: Malomed
authors.forename: Victor A
authors.initials: VA
authors.lastname: Vysloukh
authors.forename: Lluis
authors.initials: L
authors.lastname: Torner