Tuesday, January 29, 2019

Welcome to the Rollable Ribbon Party

Once dubbed "the most exciting thing to happen to black jacket cable," rollable or pliable ribbon is here to stay. Currently 5 optical fiber cable manufacturers are touting solutions in North America for the new ribbon designs, and I expect more are on the way.

As with any product offering, not all suppliers are created equal, and I would like to highlight some of the key differences in this blog. I also want to provide a comparison of splice closure capabilities as manufacturers quickly made tweaks to their existing product lines to handle the new fiber counts and designs.

First, let's take a look at what rollable ribbon is, and what the benefits are.

Instead of the traditional ribbon matrix adhesive, rollable ribbon fibers are intermittently bonded to allow the bundle of 12 fibers to flex 360 degrees. Not only does that allow a cabled assembly greater flexibility, but it also allows for more efficient utilization of the space inside the cable. This innovation has led to higher fiber counts, unique cable designs and smaller diameters.

More importantly, you can easily choose whether to splice 12 fibers in one "burn," or you can easily remove single fibers from a bundle for individual splicing. With traditional ribbon matrix, special tools were required to break out individual fibers to take special care not to disturb other fibers within the ribbon. Conversely, if you need to take a loose buffer tube and turn those fibers into a ribbon, special tool kits and adhesive are required to "ribbonize" them.

Splicing Considerations

In response to rollable ribbon bundles in the marketplace, the major fusion machine suppliers have updated their tooling to accommodate them. Adjustments were made to the jacket strippers to more effectively operate on rollable. Another important aspect to note are the coatings of each fiber in a rollable ribbon. Some designs use a 200um coating, which further helps reduce overall cable diameters. Fiber strippers for 200um as well as fiber holders are readily available. Issues may arise if you are splicing ribbons going from 250um to 200um. The alignment of all 12 fibers within the machines may be challenging, so it would be best to avoid this type of splice if possible.

Splice Closures

Based on the flexibility of the rollable ribbon, stated ribbon splice capacities of closures on the market are now generally underrated. This fiber design allows you to use shallow splice trays, which typically gives you 50% more tray space. Reduced diameters of the cable can keep everyone in tolerance with the maximum port diameter of current closure ports of 1.38." Just because you can now cram ten pounds of potatoes in a five pound bag, that only means that proper fiber management and record keeping are paramount.

From a fiber management perspective, I highly recommend ribbon breakout tubing as a means of transport to and from splice trays. You can select color coded tubing for easy identification, and they are more compact than standard transport tubes. If you leave a rollable ribbon strand unprotected, any slight buckle from moving a tray can cause individual fibers to bulge out of the bundle, leaving them exposed to snagging on other components of the closure.

Additionally for fiber management, braided sleeving wraps are ideal for express storage. They are rugged and flexible, which makes them craft friendly and compact in a space that will no doubt be filled with an abundance of splice trays. You can choose from a wide array of colors, fabrics and sizes of braided sleeving wrap, and that further helps with managing fiber groups and identification.

Not all closures are high fiber count, rollable ribbon friendly out of the box. I've compiled a list of closures on the market today that have been redesigned to work with these cables, or lend themselves well to best practices for rollable management.

High Fiber Count Ribbon to Closure Comparison 6912 5184 3456 1728 1152 864 Max Port Diameter in (mm)
Fujikura FSCO-BUW & FSCO-TN-HA (In Development) X X X X X X TBD
Sumitomo 5184F TN X X X X X 1.38 (35)
Corning (3M) 2178-XL X X X X X X 1.40 (35)
Commscope 600D XL X X X X 1.38 (35)
Preformed 9.5" x 28" Coyote High Density Dome X X X X 1.38 (35)
AFL LightGuard 350XL Sealed Dome Closure X X X 1.18 (30)
Hubbell 790 X X X 1.25 (32)

Entrance Facility

Similar to splice closures, entrance facilities have now adapted to accommodate rollable ribbon
designs. By utilizing existing trays and mass fusion technologies, you can generally use smaller cabinets for higher fiber counts if you are splicing mass. Proper fiber management is key, and utilizing breakout tubing and braided sleeving can help here as well.

Fiber Termination Panels

Rollable ribbon entered the market just as a wide selection of high port density, compact, cassette driven solutions were already hitting the road and making a significant impact in the data center market. Many of these designs are well-suited for high fiber count, rollable ribbon cables, but there are some additional concerns.

You have to look at these panels as if they are more of a distribution style platform than just a traditional in/out LGX 4RU solution. Port holes between chassis become essential for any fiber count that can't be distributed within a single enclosure. Cassettes must be easy to access with plenty of slack management for transport tubes behind them. The ability to install cassettes from the front or back of the enclosure makes a much more craft friendly design. Do not forget considerations for front-end fiber management. If the cassettes are staggered, individual fiber access is simplified. The ability to safely remove a cassette from the chassis for additional discreet port access should be another benefit to take advantage of, when available.

When the cost per RU is at stake, these high density panels already prove there worth. There are multiple designs out there, and we can help you evaluate samples to see which options work best for your needs and splicers' preferences.

Time to go MPO?

Splice on MPO/MTP connectors have been out for some time, and the major fusion machine suppliers have connectors and termination kits in their portfolios to accommodate rollable as well as traditional ribbon. Whether you want to splice on a connector or fanout, MPOs are a proven solution. These can be used for initial testing of installed fiber as well. The ability to identify, inspect and test MPO connected fibers has evolved to an efficient, effective and economical means of certification.

The Wrap Up

While the first applications for rollable ribbon were for hyperscale data centers and data center interconnect, it certainly doesn't end there. The benefits of larger, flexible cables are also being utilized by metro and residential service providers. Many contractors are already familiar with the product, and projects are kicking off nationwide with great success. Check out our Fiber Optic Cable Solutions Guide for a snapshot of each supplier's design and capabilities. If you would like to see a live demo of rollable ribbon splicing, fiber management or MPO connectorization, contact a Comstar Sales Representative today.

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