Fig. 1. The output spectra obtained based on the soliton self-frequency shift effect^[20]

Fig. 2. Experimental setup of wavelength tunable femtosecond light source based on high power erbium-doped fiber laser system^[30]

Fig. 3. Filtered optical spectra from 2-cm HNLF. Measured autocorrelation traces (red solid line) and autocorrelation traces calculated from the transform-limited pulses (black dashed line)^[30]

Fig. 4. Schematic of the 1.7 μm mode-locked bismuth-doped fiber laser^[33]

Fig. 5. The autocorrelation traces of the pulse before the compression (red) and after the external pulse compression (blue). Inset: the output optical spectrum^[33]

Fig. 6. Schematic of the NALM-based mode-locked bismuth-doped fiber laser at 1.7 μm^[34]

Fig. 7. (a) Spectra and (b) autocorrelations of the oscillator and amplifier; (c) Pulse train of the oscillator pulses; (d) Autocorrelation trace of compressed pulse^[34]

Fig. 7. [in Chinese]

Fig. 8. Schematic of the 1.7 μm Tm-Ho mode-locked fiber laser^[24]

Fig. 9. (a) Spectrum and (b) the autocorrelation of the pulse obtained at 1735 nm^[24]

Fig. 10. Schematic of the 1.7 μm mode-locked TDFL associated with the CPA system^[41]

Fig. 11. Characterization of the 1.7 μm Tm-doped mode-locked fiber laser. (a) Optical spectrum; (b) RF spectrum; (c) Oscilloscope trace of the pulse train^[41]

Fig. 12. (a) The optical spectra of the laser signal after CIR1, DCF, and CIR2. Inset: the measured power of the amplified laser versus the launched pump power and the corresponding linear fitting curve; (b) AC trace of the compressed pulse: measurement(black) and Gaussian fitting(red). Inset: RF spectrum of the amplified pulse^[41]

Fig. 13. Schematic of the W-type NDTDF based master oscillator power fiber amplifier^[44]

Fig. 14. (a) Spectra of amplified pulses with respect to pump power; (b) Output power versus pump power; (c) Measured autocorrelator trace at the full power^[44]

Fig. 15. Schematic of the all-fiber ultrafast CPA based on NDTDF^[45]

Fig. 16. Oscillator: (a) Output optical spectrum; (b) Trace of pulse trains; (c) RF spectrum; compressed pulses: (d) Output optical spectra; (e) Output power and pulse width versus launched pump power; (f) AC trace^[45]

Fig. 17. Schematic of the dissipative soliton Tm-doped fiber laser^[49]

Fig. 18. Single-pulse operation. (a) Mode-locked spectrum; (b) Pulse train, inset: pulse train over 60 μs; (c) The measured autocorrelation trace of the uncompressed output pulse (blue) and the compressed pulse (red); (d) RF spectrum^[49]

Fig. 19. Schematic of the 1.7 µm Tm-doped CPA system^[53]

Fig. 20. Optical spectra of the laser signal after the DCF (green), the pre- amplifier (blue) at the pump power of 1.5 W and the main-amplifier (red) at the pump power of 5 W. Inset: spectrum of main-amplifier^[53]

Fig. 21. (a) Output power of amplified pulse versus launched pump power; (b) Measured compressed pulse spectrum at average power of 1.3 W; (c) Autocorrelation trace; (d) RF spectrum; Inset: RF spectrum over 500 MHz frequency range^[53]