Fig. 1. Structure diagram of 2 μm fiber laser based on hybrid mode-locking structure of nonlinear polarization rotation and semiconductor saturable aborber mirror

Fig. 2. Soliton molecules mode-locking

Fig. 3. Frequency spectra of soliton molecules

Fig. 4. Harmonic mode-locking

Fig. 5. Soliton clusters

Fig. 6. Noise-like pulse mode-locking

Fig. 7. Noise-like pulse wavelength tuning