Fig. 1. Experiment setup of dumbbell-shaped all-fiber mode-locked EYDF fiber laser.

Fig. 2. The output optical spectra of ASE and CW of EYDF1 and EYDF2.

Fig. 3. (a) Output pulse waveforms, and (b) optical spectra evolution at different pump power of EYDF1; (c) autocorrelation trace over a 50 ps span for EYDF1 (the inset shows the autocorrelation trace with 5 ps span); (d) RF spectrum at the fundamental frequency for EYDF1 (the inset shows broadband RF spectra with 100 MHz span); (e) output pulse waveforms, and (f) optical spectra evolution at different pump power of EYDF2.

Fig. 4. Output power and peak power versus pump power.

Fig. 5. (a) Output spectra at different at different additional insertion loss; (b) average output power, (c) pulse duration and peak power versus pump power at different additional insertion loss.