title: High energy noise-like pulsing in a double-clad Er/Yb figure-of-eight fiber laser.
abstract: In this work, we study a 215-m-long figure-of-eight fiber laser including a double-clad erbium-ytterbium fiber and a nonlinear optical loop mirror based on nonlinear polarization evolution. For proper adjustments, self-starting passive mode-locking is obtained. Measurements show that the mode-locked pulses actually are noise-like pulses, by analyzing the autocorrelation, scope traces and the very broad and flat spectrum extending over a record bandwidth of more than 200 nm, beyond the 1750 nm upper wavelength limit of the optical spectrum analyzer. Noise-like pulsing was observed for moderate and high pump power preserving the same behavior, reaching pulse energies as high as 300 nJ, with pulse durations of a few tens of ns and a coherence length in the order of 1 ps. Stable fundamental mode locking as well as harmonic mode locking up to the 6th order were observed. The bandwidth was further extended to more than 450 nm when a 100-m piece of highly nonlinear fiber was inserted at the laser output. The enhanced performances obtained compared to other similar schemes could be related to the absence of a polarizer in the present setup, so that the state of polarization along the cavity is no longer restricted.
authors.forename: J P
authors.initials: JP
authors.lastname: Lauterio-Cruz
authors.forename: J C
authors.initials: JC
authors.lastname: Hernandez-Garcia
authors.forename: O
authors.initials: O
authors.lastname: Pottiez
authors.forename: J M
authors.initials: JM
authors.lastname: Estudillo-Ayala
authors.forename: E A
authors.initials: EA
authors.lastname: Kuzin
authors.forename: R
authors.initials: R
authors.lastname: Rojas-Laguna
authors.forename: H
authors.initials: H
authors.lastname: Santiago-Hernandez
authors.forename: D
authors.initials: D
authors.lastname: Jauregui-Vazquez