title: Ytterbium-doped fibers fabricated with atomic layer deposition method.
abstract: We report on a new fabrication method of producing ytterbium doped fibers by atomic layer deposition (ALD) in combination with the conventional modified chemical vapor deposition (MCVD) technique. An MCVD soot-preform with a porous layer of SiO(2) is coated with layers of Yb(2)O(3) and Al(2)O(3) prior to sintering, using the gas-phase ALD method. An SEM/EDS material analysis study shows that the dopants successfully penetrate the full thickness of 320 µm of the soot layer. An Yb-doped fiber fabricated by this technique shows a background attenuation of 20 dB/km, a uniform longitudinal Yb-doping profile, and good laser characteristics with a slope efficiency of 80%. Furthermore, we present a comparison in terms of photodarkening between the MCVD-ALD fiber and a solution doped fiber, fabricated with the same MCVD recipe. The new MCVD-ALD fiber appears to be more photodarkening resistant.
authors.affiliation: Aalto University School of Electrical Engineering, Tietotie 3, FIN-02015 Finland. joan.montiel@aalto.fi
authors.forename: Joan J
authors.initials: JJ
authors.lastname: Montiel i Ponsoda
authors.forename: Lars
authors.initials: L
authors.lastname: Norin
authors.forename: Changgeng
authors.initials: C
authors.lastname: Ye
authors.forename: Markus
authors.initials: M
authors.lastname: Bosund
authors.forename: Mikko J
authors.initials: MJ
authors.lastname: Söderlund
authors.forename: Ari
authors.initials: A
authors.lastname: Tervonen
authors.forename: Seppo
authors.initials: S
authors.lastname: Honkanen