Fig. 1. Schematic of the compact dumbbell-shaped ML-TDFL.

Fig. 2. (a) Optical spectral evolution under the pump powers of 2.63, 3.20, 4.35, and 5.49 W. (b) Optical spectra of both mode locking and CW at the pump power of 5.49 W.

Fig. 3. Output time-domain characteristics. (a) Single pulse envelopes with different pump powers. (b) The pulse duration as a function of the pump power. (c) Typical pulse trains at the pump power of 5.49 W.

Fig. 4. Output frequency domain characteristics. (a) The RF spectra evolution as a function of pump power. (b) The widespan RF spectrum up to 100 MHz at the pump power of 5.49 W. (c) RF output spectrum at the fundamental frequency at the pump power of 5.49 W.

Fig. 5. (a) Average output power as a function of pump power. (b) Peak power and pulse energy as functions of pump power.