title: Generation of sub-7-cycle optical pulses from a mode-locked ytterbium-doped single-mode fiber oscillator pumped by polarization-combined 915 nm laser diodes.
abstract: We report on a passively mode-locked ytterbium-doped fiber oscillator pumped by polarization-combined diodes emitting at a wavelength of 915 nm instead of 976 nm. Stable mode-locked operation based on nonlinear polarization evolution generated a broad spectrum of 140 nm, spanning from 950 to 1090 nm. The output power was 16.3 mW at a repetition rate of 93.1 MHz. External compression using a pair of transmission gratings resulted in pulse durations as short as 21.6 fs, which is equivalent to 6.6 cycle optical pulses at a wavelength of around 1000 nm.
authors.affiliation: Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871, Japan. t‑kurita@crl.hpk.co.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Kurita
authors.forename: Hidetsugu
authors.initials: H
authors.lastname: Yoshida
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kawashima
authors.forename: Noriaki
authors.initials: N
authors.lastname: Miyanaga