Fig. 1. (a) Schematic of micro-fiber loop; (b) optical microscopy photo of fabricated micro-fiber loop

Fig. 2. (a) Experimental setup for measuring the transmission spectrum of micro-fiber loop; (b) transmission spectrum of micro-fiber loop

Fig. 3. Setup for multiwavelength mode-locked fiber laser with micro-fiber loop

Fig. 4. (a) Dual-wavelength mode-locked pulse train; (b) dual-wavelength optical spectrum

Fig. 5. Output spectrum of mode-locked fiber laser without micro-fiber loop

Fig. 6. Mode-locked pulse evolution plots versus the pump power