Fig. 1. Schematic diagram of (a) NOLM and (b) NALM mode-locked laser

Fig. 2. Relationship between nonlinear phase offset difference and transmittance under different coupler ratios before and after ignore Δφ_NL

Fig. 3. Experimental results. (a) Relationship between nonlinear phase offset difference and transmittance with or without phase shifter; (b) effect of cavity loss on transmittance

Fig. 4. Structure of reflective phase shifter with separated device

Fig. 5. Ring fiber laser structure

Fig. 6. Relationship between laser threshold and doping concentration

Fig. 7. Experimental structures. (a) Transmission type phase shifter laser; (b) phase shifter laser with reflective separation device; (c) phase shifter laser with reflective spatial optical path

Fig. 8. Laser spectrogram. (a) nLIGHT fiber laser; (b) iXblue fiber laser; (c) phase shifter laser with reflective separation device

Fig. 9. Laser spectra. (a) nLIGHT fiber laser; (b) iXblue fiber laser; (c) phase shifter laser with reflective separation device

Fig. 10. Spectra and fitting curves of lasers in linear coordinates. (a) Laser 3; (b) laser 2