Passively mode-locked lasers using saturable absorber incorporating dispersed single-wall carbon nanotubes

Passively mode-locked lasers using saturable absorber incorporating dispersed single-wall carbon nanotubes (SWCNTs) is demonstrated. The peak absorption wavelength of saturable absorber can be engineered within the gain band-width of erbium-doped fiber (EDF) centered at 1550 nm. The mean diameter of SWCNTs and the linear optical absorption of SWCNTs-polyvinyl alcohol (PVA) film are verified by Raman spectroscopy and UV-Visible-NIR spectrophotometer. By integrating the SWCNTs-PVA film into EDF ring laser (EDFL) centered at 1550 nm, we observed three pulse mode operations, Q-switching, mode-locking, and 5
^th
-order harmonic mode-locking. The measured pulsewidths of the mode-locking and 5
^th
harmonic mode-locking EDFL are 4.2 ps and 2.7 ps, respectively.