Fig. 1. Schematic diagram of Brillouin laser side-mode suppression. (a) Multi-longitudinal mode; (b) single-longitudinal mode

Fig. 2. Fitting of fiber resonator ring-down curves

Fig. 3. Experimental link diagram of mode narrow linewidth Brillouin laser

Fig. 4. Test methods of Brillouin laser linewidth. (a) Delayed self-heterodyne method; (b) reference laser heterodyne method; (c) common cavity laser heterodyne method

Fig. 5. Test results of Brillouin laser side-mode suppression ratio with different powers

Fig. 6. Measurement results of Brillouin laser linewidth. (a) Frequency noise measurement results; (b) linewidth measurement and fitting results