Fig. 1. Experimental setup for mode-locked fiber laser based on NPR

Fig. 2. Traditional soliton mode locking. (a) Spectrum; (b) pulse train; (c) autocorrelation trace; (d) RF spectrum

Fig. 3. Rectangular noise-like pulse. (a) Spectrum; (b) pulse train (inset: autocorrelation trace); (c) pulse evolution versus pump power; (d) pulse width and energy versus pump power

Fig. 4. Q-switched mode-locked rectangular noise-like pulses under different pump powers

Fig. 5. Experimental results. (a) Spectral evolution; (b) autocorrelation trace

Fig. 6. Variation of Q-switched mode-locked rectangular noise-like pulses characteristics. (a) Repetition rate and output power versus pump power; (b) envelope width and pulse width versus pump power; (c) energy of a single envelope and number of pulse in envelope versus pump power; (d) average energy and peak power of QML rectangular noise-like pulse versus pump power