Abstract

Cable television operators have been using hybrid fiber-coax (HFC) networks, with the migration beginning in the late 1980s. Prior to that they had used long cascades of amplifiers, with their attendant noise, distortion, and reliability problems. Fiber’s advantages in terms of reliability and signal quality, as well as the ability to serve smaller numbers of customers from one “grouping,” or node, has encouraged HFC operators to reduce the size of nodes as much as possible, with the ultimate goal, now realizable, of a grouping of one. This is called fiber-to-the- home (FTTH). Fiber can also be run to the business (FTTB), and we sometimes use the term FTTx to mean fiber-to-the-wherever.

Fiber delivery to or near the premises has progressed to the point that it can be incorporated into HFC networks for new opportunities without affecting existing HFC plant. Fiber is a very efficient way to deliver the triple play of video, voice and data. It is used where new plant must be constructed anyway, and can interface with the existing headend and HFC infrastructure. The first customer can be connected with little or no expense incurred in the headend, through the use of a node-like tapped architecture designed for compatibility with HFC plant. The ability to deal with the RF return needs of existing set top terminals allows the operator to continue doing business as he does now.

FTTx offers higher quality modulated broadcast signals than can HFC networks, combined with much, much more data bandwidth than even advanced DOCSIS systems can offer. Data rates can be symmetrical, meaning that the total upstream and downstream bandwidths can be equal, though how the bandwidth is sold is at the discretion of the operator. Residential bandwidth has proven to be more nearly symmetrical than anticipated. Integrated termination equipment for video, voice and data is available in several configurations. The systems have completely separate broadcast and data paths, so that no RF spectrum is taken for data or voice services. Rather, the entire 54-870 MHz band can be used for broadcast video, both analog and digital.¹ Standard set top terminal (STT) RF return systems can be supported. In addition, video on IP (IPTV) has been shown to work well in the system.

© 2005 Optical Society of America