26. Introduction to Optical Access Networks

Fixed-access networks have had a tremendous impact on society over the last few decades enabling residential broadband services and being a driver for the digitalization of society. With increasing broadband speeds, optical access technologies are playing an increasingly important role for fixed access. Growing capacity demand is driving deeper fiber penetration and fiber-to-the-home () deployments. An important category of optical access systems is passive optical networks (s). PON systems are designed to meet the requirements of access networks, supporting cost effective deployment and high-end user peak rates. Several generations of PONs have been specified both in ITU-T and IEEE. Deployed systems have predominantly been based on time division multiplexing ()-PON. Recent standardization in ITU-T have specified next-generation (NG)-PON2, which is the first multi-wavelength access standard. Beyond higher capacity residential access, optical access is also expected to play an increasingly important role in providing transport services for mobile networks, supporting growing data rates and denser radio access networks. This introductory chapter on optical-access reviews the evolution of fixed-access network architecture and presents a technology overview of optical access systems.