Bright/dark switchable mode-locked fiber laser based on black phosphorus

Stable bright/dark switchable mode-locked nanosecond pulse fiber laser incorporating black phosphorus (BP) was demonstrated in the Yb-doped fiber ring cavity for the first time, to the best of our knowledge. The high-quality BP saturable absorber (SA) was fabricated by the modified electrochemical delamination exfoliation process. The states between bright and dark pulse could be switched by simply adjusting the intra-cavity polarization states, and close agreement with the cubic Ginzburg-Landau equation (CGLE) models is present.