Fig. 1. Schematic of the experimental setup: LD, laser diode; WDM, wavelength division multiplexer; OC, optical coupler; SA, saturable absorber; EDF, Er-doped fiber; SMF, single mode fiber; OI, optical isolator; RP, residual pump.

Fig. 2. ML output of the dual-wavelength oscillator at the pump power of 530 mW. Experimentally observed ML (a) output power and operating status of the laser vs. the pump power, (b) autocorrelation trace (inset: pulse train), (c) spectra of dual-wavelength and each single wavelength (inset: spectra measured at a 5 min interval over 45 min), and (d) RF spectra of dual-wavelength and each single wavelength (inset: RF spectrum measured in the 1 GHz range).

Fig. 3. (a) ASE spectra and (b) ML output spectra versus different lengths of EDF when the length of the SMF is fixed at 0 m.

Fig. 4. (a) Pulse trains and (b) ML output spectra versus different intracavity dispersions when the EDF length is fixed at 0.3 m.