Triple-Play Service Deployment

Chapter 3: Deploying and Troubleshooting Fiber Networks
Stages 1 and 2: PON Feeder and distribution cable construction
For a PON application, the optical cable containing the fibers is laid
using one of three methods.
1. Direct burial installation—The optical cable is inserted in direct
contact with the soil. It is laid either in a pre-dug ditch or via
simultaneously plowing a slot and inserting the cable.This is the
most expensive method and is used only for high-density
population areas.
2. Duct installation—The optical cable is placed inside a preinstalled
duct that runs between access points.
3. Aerial installation—The optical cable is placed on poles or
towers, allowing routing of the optical transmission path above
ground. This is the method of choice for network overlaid
(brownfield) applications.
Feeder and the distribution sections then may be spliced in an
enclosure, either to join two cables or to divide one large cable
into multiple smaller cables to diverge to different locations.
Cables and fibers can be of any type, depending on the application
and the density, including loose tube or ribbon fiber. Light, battery
operated fusion splicers—some with the capability to estimate
splice loss—have been designed specifically for FTTx applications.
However, fusion splicing is still complex and time-consuming
because it requires managing the fiber in the splice tray, cleaning
and cleaving the fiber, then splicing the fiber as well as closing the
splice enclosure. Another method of deploying the distribution
cable is to pre-engineer and build the entire fiber section, which is
placed on deployment reels. The cable is then laid out and
terminated with limited need for additional field splicing.
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