A 3-D printed saturable absorber for femtosecond mode-locking of a fiber laser

In recent years, three-dimensional (3-D) printing has presented a new manufacturing paradigm and attracted considerable attention since it allows for products to be fabricated as solid objects by printing successive layers of material following instructions produced through computer-aided design. Here, for the first time, the 3-D printing technology based on fused deposition modeling is demonstrated to be readily useful in the fabrication of a fiberized saturable absorber (SA) intended for use in ultrafast mode-locking of an all-fiberized laser. The fiberized SA was fabricated on a side polished fiber platform by printing a low-cost composite of graphene and polylactic acid (PLA). The insertion loss and modulation depth of the fabricated SA were measured to be ∼3.8 and 1.2 dB, respectively. The saturation power and the modulation depth for the transverse electric (TE) mode were estimated to be ∼16 W and ∼2.2%, respectively, while the values for the transverse magnetic (TM) mode were ∼24 W and ∼1.5%, respectively. Using the fabricated SA in an erbium fiber ring cavity, stable femtosecond soliton pulses was readily produced at 1560.2 nm. To the best of the authors’ knowledge this is the first experimental demonstration using 3-D printing technology to implement a fiberized saturable absorber.