Fig. 1. Schematic of the three-filter-response switchable microwave photonic filter based on MRR and FBG

Fig. 2. Realization and simulation of the bandpass response. (a) Realization of the bandpass response; (b) relative positions of FBG reflectance spectrum, MRR notch, and optical carrier when obtaining bandpass response; (c) MPF frequency response with the different frequencies of optical carriers

Fig. 3. Realization and simulation of the flat-top bandpass response. (a) Realization of the flat-top bandpass response; (b) relative positions of FBG reflectance spectrum, MRR notch, and optical carrier when obtaining flat-top bandpass response; (c) MPF frequency response with the different frequencies of MRR notch

Fig. 4. Realization and simulation of the high-pass response. (a) Realization of the high-pass response; (b) relative positions of FBG reflectance spectrum, MRR notch, and optical carrier when obtaining high-pass response; (c) frequency response of MPF with the different frequencies of MRR notch

Fig. 5. Examination of the prepared MRR. (a) Light microscope image and scanning electron microscope image of the fabricated MRR; (b) transmission response of the fabricated MRR; (c) thermal tuning properties of the MRR

Fig. 6. Test link of the three-filter-response switchable microwave photonic filters based on MRR and FBG

Fig. 7. Reflection spectrum of FBG and test results of three-filter-response switchable microwave photonic filters based on MRR and FBG. (a) Reflection spectrum of FBG; (b) obtained bandpass responses under different optical carrier wavelengths, when the wavelength center of MRR notch is 1542.082 nm; (c) obtained flat-top bandpass responses of MRR under different voltages, when wavelength of optical carrier is 1541.994 nm; (d) obtained high-pass responses of MRR under different voltages, when wavelength of optical carrier is 1542.110 nm