Many service providers are in the process of upgrading their networks for delivery of high-bandwidth broadband services, or plan to soon. They know it’s important to prepare for the future today. Fiber cable management--how fiber cables are connected, terminated, routed, spliced, stored, and handled — has a huge impact on every data network. Proper fiber management is critical as it has a direct effect on the network’s performance, stability, reliability, and cost.
Figure 1: Expected mechanical reliability in various optical networks
Figure 2: Change in attenuation when handling an active fiber
Bend radius control
Every fiber must be routed with physical protection in mind. Without it, fibers are susceptible to uncontrolled bends which cause transient optical losses and damage that can affect network performance and reliability.
When technicians handle fiber cables, the cables are susceptible to uncontrolled bends. As a cable is bent, its radius can become too small, allowing light to escape the core and enter the cladding. At best, the result is an increase in signal attenuation. At worst, the signal is decreased or completely lost due to a mechanical fiber fracture.
Uncontrolled bends can also occur when new fibers are added on top of installed fibers, if they’re routed over an unprotected bend. A fiber that’s been working fine for years can suddenly have an increased level of attenuation, and a shorter service life.
New bend-insensitive fiber products can give providers more leeway, but do not diminish the need for solid fiber cable management. On the contrary, the increase in the sheer number of fibers being added to systems to accommodate broadband upgrades makes bend radius control as important as ever.
Cable routing paths
The quality of cable routing paths, particularly within a frame distribution system, can be the difference between congested chaos and neatly-placed, easily accessible patch cords. Well-defined routing paths ensure bend radius requirements, making for easier access to individual fibers and reducing reconfiguration time.
Modular circuit separation system
For some network operators, the easiest way to increase fiber capacity is to add as many cables as possible, resulting in overcrowded splice trays. One drawback is that during maintenance, many cables will be touched, either intentionally or by accident. This increases the chance of an uncontrolled fiber bend. In locations that require frequent interventions, such as the access network, it makes sense to separate optical fiber circuits by storing them on individual splice trays. That way the trays can be changed to suit the desired application.
Providers planning for centralized, high-density fiber distribution are replacing 102mm and 132mm raceway systems with 610mm raceways. These larger systems not only accommodate today’s fiber requirements, but also those expected in the future.
Network operators planning for the future are also thinking about their active optical equipment: they’re insisting that cable management is included within every piece of active equipment they buy, to ensure it will operate at peak efficiently over time.
Fiber identification and cable access
Today’s active equipment rack might have 50 exiting fibers, and managing those fibers isn’t much of an issue. But as that rack is fitted for next-generation broadband services, there may be as many as 500 fibers involved, making proper management, identification, and accessibility vitally important. Connection point identification (CPID) patch cords let technicians identify particular cable runs with no chance of error.
Proper fiber management can mean the difference between network reconfigurations of 20 minutes per fiber, and one of 90 minutes per fiber. And with huge amounts of data–as well as revenue–moving across those fibers, the ability for technicians to have quick, correct, and easy access is critical. When there are service level agreements for customers with high-priority traffic, the last thing a network provider wants is service interruptions caused by mishandling one fiber to gain access to another.
Daniel Daems is Senior R&D Manager of the Fiber Optic Technology and Standards Department at CommScope Belgium