Contents 1. Introduction
The demand for wireless access has been rapidly expanding due to the high-speed wireless terminals. In addition, mobile traffic offload and low latency become key issues in future radio access networks. Therefore, there is no doubt that optical access networks for supporting the radio access networks will take on an increasingly important role. To realize future mobile services, which will require higher bit rates with higher radio carrier frequencies, a cell size covered by one radio access point must be smaller from the physical viewpoint, leading to drastic increases in the number of antennas as radio access points [1]. For the purpose of mobile back-/front-haul, optical and wireless convergence is one of hot topics in optical access networks. Hence, physically seamless connection between radio and optical links is highly desired and radio-over-fiber (RoF) technology is a strong candidate for realizing such seamless connectivity.
