Fig. 1. Principle of microwave photonics frequency measurement technology

Fig. 2. Photonics microwave spectrum analysis based on tunable FP filter^[1]

Fig. 3. Photonics microwave spectrum analysis based on SBS effect^[5]

Fig. 4. Photonics microwave spectrum analysis based on on-chip Brillouin filter^[11]

Fig. 5. Photonics microwave frequency measurement based on microwave power-frequency mapping^[13]. (a) Experimental setup;(b) power fading curve and ACF

Fig. 6. Microwave photonics frequency measurement based on optical mixing unit implemented two cascaded MZMs^[30]

Fig. 7. Microwave photonics frequency measurement based on optical mixing unit implemented highly nonlinear fiber^[32]

Fig. 8. Photonics microwave frequency measurement based on optical power-frequency mapping implementing by dual-sources and single filter^[37]. (a) Experimental setup;(b) filter responses and ACF

Fig. 9. Photonics microwave frequency measurement based on optical power-frequency mapping implementing by single source and complementary filters pair^[38]. (a) Experimental setup; (b) transmission responses of the complementary filter pair

Fig. 10. Photonics microwave frequency measurement based on optical power-frequency mapping implementing by single source and FBG filter^[41]. (a) Experimental setup;(b) reflection and transmission output power and ACF

Fig. 11. Wide spectrum dynamic microwave frequency recognition based on silicon Bragg grating^[43]

Fig. 12. Space division multiplexing microwave channelization based on free space diffraction grating^[48]

Fig. 13. Frequency division multiplexing microwave channelization based on spectrum slicing incoherent source^[49]

Fig. 14. Frequency division multiplexing microwave channelization based on SBS effect^[54]. (a) Experimental setup;(b) frequency division multiplexing channelization

Fig. 15. Time division multiplexing microwave channelization based on optical wavelength scanning source^[55]. (a) Experimental setup; (b) time division multiplexing channelization

Fig. 16. Time division multiplexing microwave channelization based on SBS and frequency shifting cyclic delay line^[57]. (a) Experimental setup; (b) time division multiplexing channelization

Fig. 17. Principle of ultrafast microwave photonics frequency measurement based on OCC transient SBS

Fig. 18. Experimental setup of ultrafast microwave photonics frequency measurement scheme based on OCC transient SBS

Fig. 19. Ultrafast frequency measurement results of microwave with single component. (a) Triangular frequency modulated microwave; (b) demodulation results of triangular microwave; (c) Costas code frequency modulated microwave; (d) demodulation results of Costas code frequency modulated microwave

Fig. 20. Ultrafast frequency measurement results of microwave with multiple components. (a) Triangular-single frequency modulated microwave; (b) demodulation results of triangular-single microwave; (c) double triangular frequency modulated microwave; (d) demodulation results of double triangular frequency modulated microwave

Fig. 21. Flow chart of demodulation algorithm based on image processing and artificial neural network

Fig. 22. Signals to be demodulated and demodulation results. (a) The measured transient spectrum to be demodulated; (b) demodulation results of two demodulation algorithms

Fig. 23. Reconfigurable instantaneous bandwidth and frequency range. (a)‒(d) Measurement range of 0.15‒1.85 GHz, 6.95‒9.3 GHz, 12‒15.4 GHz, 18.15‒19.85 GHz