Broadband Optical Access Networks

CHAPTER 4

NEXT-GENERATION BROADBAND OPTICAL ACCESS NETWORKS

In Chapters 1 to 3 we presented an overview of several broadband access technologies, the basic components and systems that are used in optical communications, and the current network architectures and protocols for time-division multiplexed passive optical networks (TDM-PONs), including BPON, GPON, EPON, and 10GEPON.

In this chapter we present and discuss further development of passive optical networks. We start by taking a look at the evolution paths currently envisioned for TDM-PON networks, mostly in terms of bandwidth increase and reach extension. Then we discuss wavelength-division multiplexed passive optical network (WDM-PON) components and network architectures that have been developed in research laboratories and have been used in a few trial deployments around the world. These WDM-PONs can provide much higher bandwidths to customers by making use of many wavelengths, in contrast to TDM-PONs, which have just one wavelength for data transmission in each direction (downstream and upstream).

We then present an overview of research hybrid TDM/WDM-PON network architectures. These network architectures allow for a progressive evolution from TDM-PON to WDM-PON. By the time WDM-PON network start being deployed, a considerable number of TDM-PON deployments will be in place. Thus, WDM-PON networks would ideally make use of the outside plant deployed for TDM-PONs, minimizing the changes to this plant and disturbing the ...