title: Thermo-optical behavior of rare-earth-doped low-NA fibers in high power operation.
abstract: The influence of the internal temperature gradient in rare-earth-doped low-numerical-aperture fibers on modal properties is analyzed for step-index and photonic crystal fibers. We provide guidelines when a single-mode fiber turns into a multimode fiber and how the mode-field-diameter is affected.
authors.forename: S
authors.initials: S
authors.lastname: Hädrich
authors.forename: T
authors.initials: T
authors.lastname: Schreiber
authors.forename: T
authors.initials: T
authors.lastname: Pertsch
authors.forename: J
authors.initials: J
authors.lastname: Limpert
authors.forename: T
authors.initials: T
authors.lastname: Peschel
authors.forename: R
authors.initials: R
authors.lastname: Eberhardt
authors.forename: A
authors.initials: A
authors.lastname: Tünnermann