High-Power RoF Link Based on Fabry–Perot Laser Diode and Phase Modulation Supporting Remote Photodiode-Drive Antenna in Next-Generation Broadband Wireless Communications

High-power radio-over-fiber (RoF) links are one of the supporting techniques to deploy remote minimalist antenna units (AUs) with photodiode-drive antenna architectures in next-generation broadband wireless communication systems. In long-haul RoF links, stimulated Brillouin scattering (SBS) is the most annoying problem, which not only limits the forward-transmitted optical power, but also severely deteriorates the signal-to-noise ratio (SNR). Here, a high-power RoF link based on a Fabry-Perot laser diode (FP-LD) and phase modulation is proposed and demonstrated to support remote photodiode-drive AUs. SBS is suppressed via optical power distribution to multiple coarse optical carriers due to the multi-longitudinal mode characteristic of the FP-LD, together with fine spectrum manipulation based on phase modulation. In the experiment, high-quality transmission of a 64-quadrature-amplitude-modulation (QAM) wireless communication signal centered at 10 GHz and with a bandwidth of 400 MHz over a spool of single-mode fiber (SMF) with a length of 10 km is demonstrated. The SBS threshold is demonstrated to be increased by more than 11 dB, and the predicted value is over 18 dB. As a result, the product of the effective transmission distance and the optical power is increased from 0.13 W⋅km to 1.7 W⋅km, and the predicted value is over 8.5 W⋅km. Under an injected optical power of 20 dBm, the error vector magnitude (EVM) and the adjacent channel leakage ratio (ACLR) reach 1.61% and -40.21 dBc, respectively. Based on this high-power RoF link, broadband wireless communication via a remote photodiode-drive AU is demonstrated.