Full-Distance A-RoF Transmission Experiment Utilizing Frequency-Optimized FM Conversion

Advances in the long-distance transmission of wideband A-RoF signals are critical. The world’s longest-class transmission using a practical A-RoF system is currently just over 300 km. In this system, CATV/BS/CS video signals are frequency-multiplexed with a bandwidth of 2.1 GHz and transmitted from broadcaster buildings to houses scattered throughout the country. In recent years, there is a demand to extend this bandwidth to 3.2 GHz in order to multiplex 8K/4K ultra-high-definition video. However, A-RoF transmission over 300 km in the 3.2-GHz bandwidth is difficult and no one has been achieved. Our solution is a new transmitter that improves transmission characteristics by changing the FM center frequency and suppressing harmonics. Our experiments clarified the existence of an optimum FM center frequency that is less affected by self-phase modulation, chromatic dispersion, and residual FM signal degradation. The proposed transmitter achieved the target distance and bandwidth for the first time in the world.