Fig. 1. Schematic diagram of NALM mode-locking

Fig. 2. Variation curves of reflectivity with nonlinear phase shift difference

Fig. 3. Structure diagram of all polarization-maintaining figure-nine cavity fiber laser

Fig. 4. Output characteristics of bound state pulses

Fig. 5. Multi-pulse mode-locked spectrum

Fig. 6. Multi-pulse mode-locked pulse sequences

Fig. 7. Signal-to-noise ratio for different numbers of multi-soliton

Fig. 8. Output characteristics of single pulses

Fig. 9. Output spectrum of linear arm

Fig. 10. Stability test of laser