Fig. 1. XRD patterns of WSSe-exfoliated crystal.

Fig. 2. (a) FESEM image of the exfoliated WSSe sample and (b) the elemental composition of the exfoliated WSSe sample.

Fig. 3. Raman spectra of the bulk and exfoliated WSSe crystal. The inset shows the Raman spectrum of the exfoliated WSSe crystal with its peaks made easier to see.

Fig. 4. Nonlinear absorption characterization of the WSSe-exfoliated crystal using the twin detection technique.

Fig. 5. Experimental setup of the C-band Q-switched EDFL with a mechanical exfoliated WSSe as an SA.

Fig. 6. Optical output of EDFL with and without incorporation of the WSSe SA.

Fig. 7. 3D pulse train evolution of the proposed EDFL against the pump power.

Fig. 8. Pulse repetition rate and pulse width of the Q-switched EDFL against the pump power.

Fig. 9. Output power and pulse energy of the Q-switched EDFL against the pump power.

Fig. 10. Radio frequency spectrum of the Q-switched YDFL at a pump power of 280.5 mW.

Fig. 11. Optical spectra of the tunable wavelength Q-switched laser at a maximum pump power of 280.5 mW.

Fig. 12. Pulse repetition rate and pulse width evolution of the proposed tunable Q-switched fiber laser at the maximum pump power of 280.5 mW.