▎ 摘　　要

We experimentally demonstrate the fabrication of an all-fiberized saturable absorber (SA) suitable for ultrafast mode-locking of a fiber laser operating in the 1.9 mu m wavelength region, using three-dimensional (3D) printing technology. An all-fiberized SA was fabricated by 3D-printing a low-cost composite filament of graphene and polylactic-acid (PLA) onto a side-polished fiber. The measured modulation depths of the fabricated SA are similar to 5% and similar to 3.5% at 1.9 mu m for the transverse electric and transverse magnetic modes, respectively. Using the SA within a thulium (Tm)-holmium-codoped fiber-based ring cavity, it is shown that modelocked pulses with a temporal width of similar to 924 fs are readily obtainable. It is believed that this experimental demonstration reaffirms the potential of the graphene/PLA filament-based 3D printing technique for the fabrication of practical wideband SAs.