title: Estimating modal instability threshold for photonic crystal rod fiber amplifiers.
abstract: We present a semi-analytic numerical model to estimate the transverse modal instability (TMI) threshold for photonic crystal rod amplifiers. The model includes thermally induced waveguide perturbations in the fiber cross section modeled with finite element simulations, and the relative intensity noise (RIN) of the seed laser, which seeds mode coupling between the fundamental and higher order mode. The TMI threshold is predicted to ~370 W - 440 W depending on RIN for the distributed modal filtering rod fiber.
authors.affiliation: DTU Fotonik, Technical University of Denmark, Ørsteds Plads building 343, 2800 Kgs. Lyngby, DK-Denmark. mmajo@fotonik.dtu.dk
authors.forename: Mette Marie
authors.initials: MM
authors.lastname: Johansen
authors.forename: Kristian Rymann
authors.initials: KR
authors.lastname: Hansen
authors.forename: Marko
authors.initials: M
authors.lastname: Laurila
authors.forename: Thomas Tanggaard
authors.initials: TT
authors.lastname: Alkeskjold
authors.forename: Jesper
authors.initials: J
authors.lastname: Lægsgaard