Solutions:   Node Segmentation Using LcWDM™

As the demand for bandwidth continues to increase (both downstream data/video from content providers and upstream data from subscribers) and clusters of homes decrease into smaller serving areas (e.g., in some cases approaching 100, 50, or even 25 homes), networks become capacity constrained or ''fiber starved.'' The most cost-effective approach to solving this problem uses multiple wavelengths on single fiber strands, and at the SCTE Cable-Tec Expo in June 2007, Aurora announced that AT3300L series 1GHz LcWDM (Low-cost Wave Division Multiplexing) transmitters are now shipping. These transmitters are ideal for the segmentation (''splitting'') of node service areas because they enable the reuse of existing fiber up to six times at distances up to 25 kilometers, and they can be combined with Aurora's NC4000 Scalable Node Platforms to increase network capacity to meet the bandwidth demands of HDTV, VoIP, VOD and high speed data services.

The many features of these LcWDM transmitters include:
•  up to six O-band wavelengths on a single fiber
•  reach of up to 25 kilometers
•  46 to 1002 MHz RF bandwidth
•  dual RF input ports with AGC for broadcast and narrowcast services
•  compatibility with existing segmentable nodes
•  ''pay as you grow'' for incremental build flexibility.

Aurora currently offers two product lines for implementing node segmentation with LcWDM transmitters and filters. One product line is based on a solution using two LcWDM wavelengths and two fibers, and a diagram depicting a 2-wavelength network design is shown below. This diagram also depicts the digital return traffic that uses the same fibers to send counter-propagating wavelengths upstream to the service provider.

The second more expansive product offering supports up to six wavelengths on a single fiber. A diagram depicting a multi-wavelength network design is shown below. In the diagram, four initially-deployed wavelengths are supplemented at later dates with two additional wavelengths to expand the number of segments served by a node and to add a node for a new service area.

Last revised 15 January 2008