Fig. 1. Microwave instantaneous frequency measurement system structure based on single lightpath polarization multiplexing

Fig. 2. The selective PM-to-IM conversion schematic based on SBS

Fig. 3. Mapping relationship between sweep frequency detection signal f_s and OPM sampling optical power.（a） f_x=5 GHz;（b） f_x=15 GHz

Fig. 4. System simulation data measurement results. (a) Comparison of input frequency and measurement frequency; (b) absolute measurement error and relative measurement error between input frequency and measurement frequency

Fig. 5. Influence of pump wavelength fluctuation on the drift of Brillouin frequency shift

Fig. 6. Influence of polarization state shift on measurement results. (a) Comparison of input frequency and measurement frequency; (b) error between input frequency and measurement frequency

Fig. 7. The influence of the phase shift of the electrical phase shifter on the DSB-SC signal sideband and OSSR.(a) 0°; (b) 5°; (c) 10°; (d) 15°

Fig. 8. The influence of DC bias point drift on ±1st order sideband power and OSSR