Stable and high energy ytterbium-doped mode-locked fiber laser based on a franckeite-polymer film modulator

Abstract

As a novel material with narrow band gap and natural van der Waals heterostructures (vdWH), francketie has potential applications in the field of optoelectronic fields. However, few studies have applied its nonlinear optical absorption properties to ultrafast fiber lasers. Here, we synthesized francketie nanosheets via the liquid-phase exfoliation (LPE) method. By incorporating the polyvinyl alcohol (PVA), a franckeite-PVA saturable absorber (SA) was fabricated to achieve a mode-locked Yb-doped fiber laser (YDFL) for the first time to the best of our knowledge. The saturation intensity and modulation depth of the SA were measured about 75 MW∕cm2 and 7%, respectively. The proposed franckeite-based YDFL demonstrates stable mode-locked operation with the maximum single energy of 5.35 nJ and the pulse duration of 1.57 ns. Our experimental results fully prove that franckeite may have wide potential for designing ultrafast photonics devices with low cost, high stability and excellent performance.