title: High-power Yb-doped photonic bandgap fiber amplifier at 1150-1200 nm.
abstract: Ytterbium-doped solid-core photonic bandgap fiber amplifiers operating at the long-wavelength edge of the ytterbium gain band are reported. The low-loss bandgap transmission window is formed in the very low gain region, whilst outside the bandgap, large attenuation inhibits the exponential growth of amplified spontaneous emission in the huge-gain 1030-1100 nm region. Hence parasitic-lasing-free, high-power amplification with a marked efficiency is enabled. A 32 W output at 1156 nm with a 66% slope efficiency and 30 W output at 1178 nm with a 58% slope efficiency were successfully obtained. To our knowledge, these are the highest output powers generating from active photonic bandgap fibers, as well as from ytterbium-doped fiber lasers at these wavelengths.
authors.affiliation: Institute for Laser Science, University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan. akira@ils.uec.ac.jp
authors.forename: A
authors.initials: A
authors.lastname: Shirakawa
authors.forename: H
authors.initials: H
authors.lastname: Maruyama
authors.forename: K
authors.initials: K
authors.lastname: Ueda
authors.forename: C B
authors.initials: CB
authors.lastname: Olausson
authors.forename: J K
authors.initials: JK
authors.lastname: Lyngsø
authors.forename: J
authors.initials: J
authors.lastname: Broeng