Effects of spectral filtering on pulse dynamics in a mode-locked fiber laser with a bandwidth tunable filter

We investigate numerically the impact of spectral filtering on pulse characteristics in anomalous dispersion erbium-doped fiber laser mode-locked with carbon nanotube-based saturable absorber. The laser can operate only in a single-pulse state without a filter, while it will transit to bound soliton states once the saturation energy of the gain fiber and the bandwidth of the filter are carefully chosen, respectively. Further analyzation shows that the operation of a single-pulse lasing from dissipative soliton to conventional soliton can be selectively targeted by changing the bandwidth of the filter through the loss and frequency narrowing effects. Laser performances, such as spectrum structure, pulse duration, pulse energy and peak power in both the frequency and the time domains, will all be affected. This paper provides a guidance for the mode-locked fiber laser and proposes a feasible way to control the pulse dynamics.