Fig. 1. Structure diagram of SLM fiber laser

Fig. 2. Transmission spectrum of FBG

Fig. 3. Structure diagram of subring cavity

Fig. 4. Transmission spectrum of the proposed compound cavity filter, and the inset is the zoomed-in transmission spectrum of compound cavity filter at the central lasing wavelength

Fig. 5. Transmission spectrum of the proposed compound cavity filter with 50∶50 coupler radio, and the inset is the zoomed-in transmission spectrum of compound cavity filter at the central lasing wavelength

Fig. 6. Structure and filtering performance of the cascaded double-ring cavity. (a) Schematic of the cascaded double-ring cavity; (b) transmission spectrum of the cascaded double-ring cavity filter, and the inset is the zoomed-in transmission spectrum of the cascaded double-ring cavity filter at the central lasing wavelength

Fig. 7. Fundamental schematic of saturable absorber

Fig. 8. Output characteristics of the laser. (a) Spectrum of the laser output; (b) wavelength and power fluctuation of the output lasing within 60 min

Fig. 9. Frequency output characteristics of the proposed laser. (a) Self-homodyne radio frequency (RF) spectrum of laser in 0-100 MHz; (b) self-homodyne RF spectrum of laser in 0-500 MHz; (c) self-homodyne RF spectrum of laser in 0-1 GHz; (d) RF spectrum of the main cavity without SA; (e) relative intensity noise (RIN) spectrum of the laser

Fig. 10. Output line width and tunability of the proposed laser. (a) Power spectral density of frequency noise of the laser; (b) spectrum of the laser output with a wavelength-tunable range of 2.7 nm

Table 1. Performance index comparison of SLM TDFL based on different techniques