Fig. 1. Schematic diagram of the experimental setup

Fig. 2. Pulse output characteristics of the single-wavelength mode locking. (a) (b)(c) Spectra at 1530.8 nm, 1549.5 nm, and 1556.5 nm, respectively; (d)(e)(f) corresponding AC traces, and the inset in Fig.2 (f) is the RF trace in large range at 1556.5 nm; (g) (h) (i) corresponding RF traces, in which the insets are the corresponding oscilloscope traces at 1530.8 nm, 1549.5 nm and 1556.5 nm, respectively

Fig. 3. Spectra and oscilloscope traces of the dual-wavelength mode locking. (a)(b)(c) Spectra at 1530.8 nm-1556.5 nm, 1530.8 nm-1549.5 nm, and 1549.5 nm-1556.5 nm mode-locking states, respectively; (d)(e)(f) corresponding oscilloscope traces

Fig. 4. Pulse output characteristics of the triple-wavelength mode locking. (a) Spectrum; (b) oscilloscope trace; (c) RF spectrum, in which the inset is the close-up from the box