Fig. 1. Schematic diagram of the proposed scheme. LD, laser diode; PM-OC, polarization maintaining optical coupler; ATT, attenuator; PS, phase shifter; $90\mathrm{°}$ PR, $90\mathrm{°}$ polarization rotator; PBC, polarization beam combiner; MZM, Mach–Zehnder modulator; PD, photodiode.

Fig. 2. Experimental setup of the proposed scheme. DFB-LD, distributed feedback laser diode; IM, intensity modulator; EA, electrical amplifier; PM-OC, polarization maintaining optical coupler; ATT, attenuator; PS, phase shifter; $90\mathrm{°}$ PR, $90\mathrm{°}$ polarization rotator; PBC, polarization beam combiner; EDFA, erbium-doped fiber amplifier; PD, photodiode; HA, antenna; OSC, oscilloscope.

Fig. 3. Received electric mm-wave signal spectra and constellation diagrams for the BTB and wireless transmission: (a) BTB transmission, (b) 1 m wireless transmission. (a1), (b1) Received mm-wave signal spectra, (a2), (b2) before orthogonalization, (a3), (b3) after orthogonalization, (a4), (b4) after CMA, (a5), (b5) after FOE, and (a6), (b6) after CPE.

Fig. 4. BER versus the optical power into the PD for BTB and wireless transmission.