To the left is a close-up view of the “Edge” Access Network portion of the HFC Network where the Single Fiber, Hub-to-Node connection, from the SFC Transceivers in the Hub GbE Switch connect via the Passive Mux/Dmux in the Hub, to the Mux/Dmux in the Node, continuing to the GbE Switch CPE at the Business Class Customer Premises.
Because the HFC Network was not originally planned to support Fiber Optic connections to Commercial Customers, the Optical Fiber count in the Hub-to-Node trunks are limited, typically to Six (6) or Eight (8) Fibers. Of these Fibers, standard practice often was to allocate Two (2) to Four (4) Fibers for Residential Video and Broadband (DOCSIS), Two (2) Fibers for Future Services and Two (2) Fibers as “Spares”. Any Two-Fiber or Two Wavelength Direct (“Home-Run”) or CWDM approach will quickly exhaust the available remaining Two (2) to Four(4) Fibers. SFC immediately Doubles the Fiber Capacity, while Reducing the Part-Count of Components in Half, compared to alternative approaches. Since SFC only consumes Fibers One-at-a-Time (whereas alternatives consume Fibers in Pairs), the SFC Advantages are greatly magnified.