title: 3 GHz, fundamentally mode-locked, femtosecond Yb-fiber laser.
abstract: We demonstrate a fundamentally mode-locked Yb-fiber laser with 3 GHz repetition rate and ∼206  fs pulse duration. The laser incorporates two enabling technologies: a 1 cm heavily Yb-doped phosphate glass fiber as the gain medium and a high-dispersion (-1300  fs2) output coupler to manage cavity dispersion. The oscillator self-starts and generates up to 53 mW average power.
authors.affiliation: Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Hung-Wen
authors.initials: HW
authors.lastname: Chen
authors.forename: Guoqing
authors.initials: G
authors.lastname: Chang
authors.forename: Shanhui
authors.initials: S
authors.lastname: Xu
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Yang
authors.forename: Franz X
authors.initials: FX
authors.lastname: Kärtner