Optical access networks—an operator view from past to future system—technologies and applications [Invited]

The passive optical network (PON) has emerged as the dominant broadband access technology globally, owing to its superior bandwidth scalability, cost-effectiveness, and reliability. This paper systematically reviews the progress in standardization, the technical evolution, and practical applications of optical access networks (OANs) from an operator’s perspective. Beginning with the fundamental architecture and advantages of OAN, this paper elaborates on the development of PON technologies, including EPON/GPON, 10G-PON (XG(S)-PON/10G-EPON), and 50G-PON, with a focus on the driving forces for development, system technologies, and typical application scenarios. Furthermore, future directions of OAN are explored in two dimensions: very high-speed PON (VHSP, with integrated communication and sensing) and intelligent OAN empowered by artificial intelligence (AI) to present a thorough perspective.