All-fiber mode-locked ytterbium-doped fiber laser with a saturable absorber based on nonlinear Kerr beam cleanup effect

TL;DR

This paper presents a novel all-fiber mode-locked ytterbium-doped laser utilizing a saturable absorber based on the nonlinear Kerr beam cleanup effect, achieving stable dissipative soliton pulses with significant pulse compression.

Contribution

It introduces a new saturable absorber design using multimode and single-mode fibers for stable mode-locking in an all-normal-dispersion fiber laser.

Findings

Generated 26.38 ps pulses with >0.25 nJ energy

Externally compressed pulses to 615.7 fs

High stability with 73.4 dB SNR in RF spectrum

Abstract

We theoretically and experimentally demonstrate a novel mode-locked ytterbium-doped fiber laser with a saturable absorber based on nonlinear Kerr beam cleanup effect. The saturable absorber was formed by a 2-m graded-index multimode fiber and a single-mode fiber segment served as a diaphragm. With an all-normal-dispersion-fiber configuration, the laser generated dissipative soliton pulses with pulse duration of 26.38 ps and pulse energy more than 0.25 nJ; output pulses could be compressed externally to 615.7 fs. Moreover, the self-starting mode-locking operation of this laser exhibited a high stability with a measured signal-to-noise ratio of 73.4 dB in the RF spectrum.