Fig. 1. (a) Schematic diagram of the proposed microwave photonic frequency mixer; (b) Optical signal at the main point of the system; (c) Optically-carried local oscillator used in the experiment; (d) Photographs of the wavelength-division modulator chip

Fig. 2. Transmission response of the micro-ring filter

Fig. 3. Measured optical spectra of optical signal. (a) Coupled in the chip; (b) Coupled output from the chip

Fig. 4. Measured electrical spectra of system output. (a) ω_RF=14 GHz (in a large frequency range); (b) RF frequency tuned in a frequency range from 6 to 16 GHz

Fig. 5. Simulated frequency spectra when the rejection ratio of the micro-ring filter is (a) 10 dB and (b) 40 dB; (c) Power of 2ω_LO−ω_RF and ω_RF, and the spurs suppression ratio for the different rejection ratio of the micro-ring filter

Fig. 6. Simulated frequency spectra with (a) the maximum mixing spurs ω_RF and (b) the minimum mixing spurs ω_RF; (c) The spurs suppression ratio vs. the phase value of the optical phase shifter