title: Inscription of fiber Bragg gratings by ultraviolet femtosecond radiation.
abstract: We report on what is to our knowledge the first fabrication of fiber Bragg gratings by UV femtosecond radiation. The Bragg gratings, with photoinduced refractive-index modulation up to 1.92 x 10(-3) in H2-loaded SMF-28 and up to 1.05 x 10(-3) in Nufern GF1 fibers, were written by high-intensity (31-77-GW/cm2) femtosecond pulses at 264 nm. The dependence of the refractive-index modulation on intensity at equal fluences points to a two-photon absorption mechanism for grating inscription.
authors.affiliation: Department of Physics, National University of Ireland, University College Cork, Cork, Ireland.
authors.forename: Adrian
authors.initials: A
authors.lastname: Dragomir
authors.forename: David N
authors.initials: DN
authors.lastname: Nikogosyan
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Zagorulko
authors.forename: Peter G
authors.initials: PG
authors.lastname: Kryukov
authors.forename: Evgueni M
authors.initials: EM
authors.lastname: Dianov