Mode-locked Erbium-doped Fiber Laser Based on Single-wall Carbon Nanotubes and Fiber Focusers

In this paper, we have demonstrated a mode-locked Er-doped fiber laser based on carbon nanotube saturable absorber and a pair of fiber focusers. The nonlinearity of the absorber will change when moved away from the beam waist position of the fiber focuser and lead to different running states of the laser. The effects of spot size on the mode-locked states of the laser have also been studied.