Fig. 1. Experimental layout of the 2.9 kW tandem-pumped fiber amplifier^[28]

Fig. 2. Experimental scheme of the tandem-pumped ytterbium-doped phosphosilicate fiber amplifier^[30]

Fig. 3. Experimental setup of the tandem-pumped all-fiber narrow linewidth amplifier^[31]

Fig. 4. Experimental structure of the spaceborne ytterbium-doped low quantum defect fiber laser^[32]

Fig. 5. Experimental setup of the low quantum defect laser via ytterbium-doped multicomponent fluorosilicate fiber^[34]

Fig. 6. The experimental layout of the first hundred-watt-level low quantum defect Raman fiber laser^[48]

Fig. 7. Experimental scheme of the 3 kW Raman amplifier based on metal-coated graded-index passive fiber^[56]

Fig. 8. Experimental structure of the spaceborne cladding-pumped Raman fiber laser^[57]

Fig. 9. The normalized Raman gain spectra of phosphorus-doped fiber and germanium-doped fiber^[63]

Fig. 10. The Raman gain spectra of As₂S₃ glasses: (1) Well annealed sample; (2) Quenched in the air; (3) Quenched in ice water^[70]

Fig. 11. The Raman gain spectra of phosphosilicate fiber for different P₂O₅ concentrations^[74]

Fig. 12. The vibration density states spectra of of P₂O₅ glass and the related vibration modes^[69]

Fig. 13. The spatial distribution of the contribution of each particle to the excess vibration modes for different frequencies ^[75]

Fig. 14. Experimental layout of the phosphosilicate fiber based low quantum defect Raman laser^[77]

Fig. 15. Schematic diagrams of laser transmission in different pump schemes: (a) cladding pumping and (b) core pumping^[79]