Highly spectral-efficient and high capacity millimeter-wave wireless data transmission using a Coherent Radio-over-Fiber system (CRoF)

This paper reports on the development of a packaged coherent photonic mixer (CPX) for coherent Radio-over-Fiber (RoF) systems. The developed integrated CPX performs direct optical-to-RF up-conversion with a 5 dB better conversion efficiency at 60 GHz as compared to a commercially available 110 GHz photodiode. The 3 dB bandwidth and maximum RF output power of the CPX are 65 GHz and +7 dBm, respectively. By utilizing the developed CPX module in a CRoF system, we demonstrate 1 Gbit/s NRZ data transmission over 25 km long fiber and a 230 m long wireless link within the 71-76 GHz band. Furthermore, a novel IF-CRoF architecture is presented enabling high-capacity 21 Gbit/s wireless 60 GHz transmission using a 64 QAM-OFDM modulation format and record spectral-efficiency (9 bit/s/Hz) wireless transmission using a 512 QAM-OFDM modulation.