Analogue Coherent-Optical Mobile Fronthaul with Integrated Photonic Beamforming

We present a mobile fronthaul methodology for the
analogue optical transmission of native radio signals with
integrated photonic true-time delay for the beam steering of
phased-array antennas. Laser-based coherent homodyne
detectors and the delay dissemination through ultra-dense
wavelength division multiplexing ensure a low complexity at the
optical layer. We experimentally demonstrate beamsteering for a
linear phased-array antenna with a 1×3 configuration at 3.5 GHz
carrier frequency and prove native radio signal transmission
over the 14.3-km reach coherent optical fronthaul at a low endto-
end error vector magnitude of 3.3%. Experimental results are
found to stand in good agreement with theoretical predictions.