title: Distributed mode filtering rod fiber amplifier delivering 292W with improved mode stability.
abstract: We demonstrate a high power fiber (85 μm core) amplifier delivering up to 292 Watts of average output power using a mode-locked 30 ps source at 1032 nm. Utilizing a single mode distributed mode filter bandgap rod fiber, we demonstrate 44% power improvement before the threshold-like onset of mode instabilities by operating the rod fiber in a leaky waveguide regime. We investigate the guiding dynamics of the rod fiber and report a distinct bandgap blue-shifting as function of increased signal power level. Furthermore, we theoretically analyze the guiding dynamics of the DMF rod fiber and explain the bandgap blue-shifting with thermally induced refractive index change of the refractive index profile.
authors.affiliation: DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark. malau@fotonik.dtu.dk
authors.forename: Marko
authors.initials: M
authors.lastname: Laurila
authors.forename: Mette M
authors.initials: MM
authors.lastname: Jørgensen
authors.forename: Kristian R
authors.initials: KR
authors.lastname: Hansen
authors.forename: Thomas T
authors.initials: TT
authors.lastname: Alkeskjold
authors.forename: Jes
authors.initials: J
authors.lastname: Broeng
authors.forename: Jesper
authors.initials: J
authors.lastname: Lægsgaard
mesh_terms: D000669:Amplifiers, Electronic; D017076:Computer-Aided Design; D004735:Energy Transfer; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers