Initial Docsis 3.0 deployments increased during 2010 and are expected to accelerate rapidly over the next two to three years putting pressure on cable operators to allocate bandwidth in both the downstream and upstream paths. The number of added narrowcast QAM channels continues to steadily increase as a result of SDV deployments and the shift to HD content. The anticipated introduction of CMAP (Converged Multi-media Access Platform) equipment estimated for 2012 is also expected to dramatically amplify the need for even higher numbers of additional QAM channels and with it the requirements for a cost effective means to deliver these channels to smaller node serving areas and targeted customers. On top of this, new business services opportunities, cell tower backhaul, and WiFi access point deployments require a growing share of plant access network capacity.
The need for more bandwidth never sleeps which causes more than a few cable system operators to lie awake at night as they try to determine which of the numerous alternatives to meet this never ending challenge is the most cost effective and future proof. The consensus has gradually shifted away from the traditional path of expanding plant RF bandwidth and is now moving to take advantage of the broad WDM segmentation capacity of existing fiber.
Facilitating this change is a wide range of fiber architectures and Headend optical transmitter technologies ranging from expanded capability QAM lasers to new 10 Gb devices that provide a bridge between today’s analog / QAM transport requirements and the high speed IP delivery needs of the future.
This paper provides a comparison of these currently available laser transmitter technologies identifying the differentiating features and limitations of each design type along with link application examples. The impact of the all digital channel loading transition and converged services on the performance, reach, and network cost using these technologies will also be examined.