Abstract
Seamless convergence between radio and optical fiber networks is indispensable for achieving such advanced
radio access schemes as 5th generation (5G) mobile communication systems. Radio-over-fiber
(RoF) technology is a promising solution to efficiently convert radio signals into optical signals in a
physical layer and vice versa. RoF systems have already been installed as compensation for radio dead
zones on metro subway lines, mountain areas, high-rise buildings, and so on. The advantages of the RoF
are based on a low loss feature of optical fibers, the broad bandwidth capacity of the optical signals, and
low immunity to existing radio services due to the encapsulation of radio signals into optical carriers. In
this paper, we introduce RoF technology following millimeter-wave and terahertz-wave signal generation
empowered by a photonics technique and its application to such public infrastructure as high-speed
railway and radio-relay systems.
