Fig. 1. Schematic of m-RoF uplink fronthaul system using cascaded microwave photonic downconversion topology

Fig. 2. Measured optical spectra at the output. (a) MZM1; (b) MZM2

Fig. 3. Spectrum. (a) Measured optical spectrum at the output of WS; (b) electrical spectrum of generated 3 GHz IF signal

Fig. 4. Measured conversion efficiency versus different frequencies of input mm-wave signals

Fig. 5. Experimental results. (a) Measured electrical spectrum of downconverted broadband IF signal at 1.4 GHz after 1.2 m free-space and 5 km fiber transmissions; (b) constellation diagrams of the demodulated signal; calculated (c) EVM and (d) SNR for subcarriers

Fig. 6. Experimental results. (a) BER versus different center frequencies of uplink mm-wave signal; (b) BER as a function of received optical power for 5 km fiber and back-to-back transmissions

Fig. 7. Measured electrical spectra of downconverted IF signals with (a) 3 GHz and (b) 5 GHz bandwidth 4-QAM OFDM signals; constellation diagrams of the demodulated signals with (c) 3 GHz and (d) 5 GHz bandwidth 4-QAM OFDM signals