Three operation regimes with an L-band ultrafast fiber laser passively mode-locked by graphene oxide saturable absorber

We present three operation regimes with an L-band erbium-doped fiber laser passively mode-locked by a graphene oxide saturable absorber (GOSA) that is fabricated by using a wet chemical method. One is a stable state of single soliton emission with pulse duration of 426 fs, which is the shortest pulse duration ever achieved with an L-band design by employing GOSA as the mode-locker. The other two operation regimes include bound-state soliton and dual-wavelength nanosecond pulse generation, which are demonstrated for the first time by using the GOSA mode-locker. Our results further indicate the practical potential of GOSA in ultrafast fiber lasers for achieving various mode-locking regimes.