Fig. 1. Schematic of typical passive mode-locked fiber oscillator

Fig. 2. Mamyshev oscillator.(a) Schematic of the principle of Mamyshev oscillator^[53]; (b) schematic of Mamyshev oscillator with MW-order peak power^[55]

Fig. 3. High repetition rate fiber laser. (a) Mode-locked fiber laser with 1 GHz repetition rate^[62]; (b) mode-locked fiber laser based on Fabry-Perot cavity with repetition rate of 12.5 GHz^[64]

Fig. 4. Mode-locked fiber laser based on NALM^[69]. (a) Schematic of the resonant cavity; (b) relationship between output energy pulse width and single mode fiber length; (c) relationship between output waveform and single mode fiber length

Fig. 5. High average power fiber laser with NALM^[74]. (a) Schematic of all-polarization-maintaining mode-locked fiber laser with NALM; (b) relationship between average power and pump power; (c) power stability over 4 h

Fig. 6. Effect on pulse splitting threshold^[17]. (a)Simulated results at different ΔL; (b) experimental results at different ΔL

Fig. 7. Experiment on DSR^[46]. (a) Schematic of the DSR laser; (b) pulse width and output power versus NALM loop pump power; (c) pulse energy and peak power versus NALM loop pump power

Fig. 8. Soliton explosion in mode-locked fiber laser^[103]. (a) Continuous spectrum evolution; (b) spectrogram under certain number of cycles

Fig. 9. Evolution of pulsating soliton formation in short time scale^[105]. (a)(c)Spectral evolution recorded by DFT; (b)(d)peak power and bandwidth evolution; (e) spectra under certain number of cycles; (f)experimental path

Fig. 10. Properties of microfiber^[106-108]. (a)(b) Calculated second-order dispersion of micro-nano fibers with different diameters at around 1 μm and 2 μm wavelength; (c) calculated effective nonlinear coefficient of micro-nano fibers with different diameters; (d) measured insertion loss of micro-nano fiber with a diameter of 1 μm

Fig. 11. Mode-locked fiber laser based on microfiber^[109-110]. (a)(c) Schematic of micro-nano fiber-based mode-locked fiber lasers with around 1 μm and 2 μm wavelength; (b)(d) corresponding spectra of ultrashort pulse

Fig. 12. Microfiber for other laser applications. (a)(c)Optical structure of Yb-doped fiber oscillator based on micro-nano fiber; (b)(d) corresponding 1 μm-band noise-like spectra; (e)--(g) in the reflective output optical path, noise-like spectra of 2 μm-band dispersion modulated by the micro-nano fiber; (h)(i) photogragh and optical spectrum of simultaneouse third harmonic generation in the micro-nano fiber