In this work we propose a simple, all-fiber dispersion managed Ho-doped laser mode-locked with graphene saturable absorber (SA). Dispersion compensating fiber was used to balance the anomalous dispersion of the active and standard single mode fibers, which allows to overcome the limitations set by soliton area theorem. The laser was pumped by a custom-made 1940 nm thulium-doped fiber laser delivering up to 3 W of power. Graphene/PMMA composite sandwiched between fiber connectors serves as a fully fiberized SA. The generated Gaussian pulses centered at 2059 nm reached 53.6 nm of bandwidth. Compressing the pulses by guiding it through SMF-28 fiber yields pulse durations of 190 fs. We also compare the graphene-based laser with a setup mode-locked with nonlinear polarization rotation - an artificial SA.

To the best of our knowledge, this is a first demonstration of a nanomaterial-based stretched pulse fiber laser operating beyond 2 μm. The all-fiber cavity is a more robust alternative to setups that include bulk optics, and requires significantly less alignment compared to lasers mode-locked with real SAs