Fig. 1. Schematic diagram of the experiment setup.

Fig. 2. Mode-locking operation of single and multiple solitons at different pump powers. Single soliton at 665 mW: (a) optical spectrum, (b) temporal pulse train, and (c) RF spectrum. Multiple solitons at 925 mW: (d) optical spectrum, (e) temporal pulse trains, (f) close-up of the temporal pulse trains for multiple solitons in (e), (g) RF spectrum with a 1 MHz span, and (h) autocorrelation trace.

Fig. 3. Spatiotemporal evolution diagrams of multiple solitons at different pump powers. (a) 1025 mW, (b) 1225 mW.

Fig. 4. Soliton bunch characteristics under varying pump powers. (a) Pulse number in single round trip versus pump power; (b) average pulse separation in single round trip versus pump power; (c) pulse number’s dependency on the pump power; (d) average pulse width within a soliton bunch versus pump power; (e) optical spectra; and (f) average output power’s dependency on pump power.

Fig. 5. (a) Numerical simulation of multiple solitons; (b) spatial-temporal diagram at the 13-soliton state.