Deployment of optical fibers in the last mile has been getting momentum in many parts of the world irrespective of the installation and economic concerns. While the powerful copper lobby is strong enough to pull back the progress of FTTH in at least some parts of the world, the majority of the telecom operators are of the opinion that optical fiber technology is future proof and investment in fiber will not be a wrong decision.
This post is to discuss the options available last mile optical fiber cable deployment methods. The last mile can be an extension of the access or feeder network. Thus the underground network can be extended to the home or apartment. Generally for underground duct deployment, the access cables are laid in 100 mm HDPE or PVC ducts. Some telecom operators use a 75mm duct also. Duct networking for access network is done to do the connection in the access closures. Depending on the splitting option, splitters can be placed in the underground closure. Alternatively, the fibers can be spliced to the last mile cable in the underground closure.
The second method is to place the closure in a pedestal case that protects the closure from the outside environment. In this case, the access fiber cables through the ducts will be terminated in a pedestal closure. The splitting or splicing can be done in the closure and then divert the optical signals through the drop cable to subscribers. The advantage of pedestal closure is the easy maintenance. Underground closures are difficult to access. Maintenance is difficult when the closure is placed underground.
If the access cable is to be terminated or distributed in a mansion complex or housing units, the closure can be attached to the boundary wall. This is one of the alternative designs of the pedestal network. Drop closures attached to the boundary wall are easy to be accessed for maintenance work. Such network configurations help to reduce the time required for the installation of drop cables. Installation of drop cables can be done easily as and when the subscriber demand comes.
Maintenance could be much easier if the closure is placed aerially if the network configuration is aerial. Aerial drop cables can be spliced or distributed after splitting in an aerial closure. Aerial access cables that can be used for midspan access are available in the market. Aerial access fiber optic cables are able to hold the aerial drop closure on their supporting wire. The cables are designed with sufficient strength to hold the drop closure. Such types of cables take care of the wind and ice loading factors as well.
The advantage of aerial deployment of drop cables to the home is cheaper installation cost and easy maintenance. The disadvantage is the bad landscape with many cables hanging in the sky. We could read from some of the blogs that some of the Australian people got angry about NBN’s aerial deployment of fiber optic cable to their home. And still, some in Canada were angry that their garden is destroyed in order to lay ducts to their home for fiber optic drop cables.
The selection of the deployment method depends on economical and geographical factors mainly. If a geographical location is prone to more flooding, aerial access and aerial last mile deployment will be much beneficial. If there is a threat from typhoons and heavy winds underground networking will be advisable. Geographical conditions and subscriber choices decide the kind of last mile network configuration.