Investigations of switchable fiber soliton laser mode-locked by carbon nanotubes

We have numerically and experimentally investigated a switchable erbium-doped fiber (EDF) laser mode-locked by single-walled carbon nanotubes for the first time to our best knowledge. Depending on the pump power, the central wavelength of the mode-locked pulse can be switched from about 1531 to 1557 nm. The formation and evolution of the switchable soliton operation are investigated numerically by solving the extended nonlinear Schrödinger equation with the appropriate gain profile. Numerical results demonstrate that the switchable mode-locking operation is attributed to the variation of the gain spectrum of EDF, agreeing well with the experimental observations.