Contents I. Introduction
Hybrid fiber coaxial-cable (HFC) networks remain a competitive technology for cable television distribution and local access services. In typical deployments, a mix of services, such as Internet access, entertainment television, and telephone service, are delivered to and from users on a common HFC physical plant. In the electrical domain, the different information channels are multiplexed on different radio-frequency (RF) carriers, and the entire RF signal modulates the power of the lightwave carrier, thus forming a subcarrier-multiplexed signal (SCM). Historically, these HFC networks have used a single optical carrier, but more recently, wavelength-division multiplexing (WDM) has been introduced into the lightwave portion. WDM allows greater information capacity of the fiber and greater flexibility in terms of targeting signals to smaller fiber-node groups, a practice known as narrowcasting. Signals intended for multiple end-groups are carried over a common optical fiber for some part of the lightwave portion of the network, and then split to their respective receivers using a wavelength demultiplexer. As signal formats evolve and capacity demands of these systems increase, more and more information capacity is demanded of the SCM-WDM link. We address the limit of that information capacity here.
