Not long ago i watched my coworker disassembling a pc using only one tool. Was it the right tool for the job? Yes and no. It was the tool he had… it worked, however, there exists definitely multiple tool out there that would have made the task easier! This case is definitely one that many fiber optic installers know all too well. As a gentle reminder, how many of you have used your Splicer’s Tool Kit (cable knife/scissors) to remove jacketing or even slit a buffer tube and then use the scissors to hack away at the Kevlar? Did you nick the glass? Did you accidentally cut through the glass and need to start over?
Correctly splicing and terminating Secondary Coating Line requires special tools and techniques. Training is important and there are lots of excellent types of training available. Do not mix your electrical tools along with your fiber tools. Utilize the right tool for the task! Being familiar with fiber work will become increasingly necessary as the importance of data transmission speeds, fiber towards the home and fiber to the premise deployments continue to increase.
Many factors set fiber installations besides traditional electrical projects. Fiber optic glass is very fragile; it’s nominal outside diameter is 125um. The least scratch, mark or even speck of dirt will affect the transmission of light, degrading the signal. Safety factors are important since you work with glass that can sliver into your skin without being seen from the human eye. Transmission grade lasers are extremely dangerous, and require that protective eyewear is essential. This industry has primarily been working with voice and data grade circuits which could tolerate some interruption or slow down of signal. The individual speaking would repeat themselves, or even the data would retransmit. Today our company is working with IPTV signals and customers that will not tolerate pixelization, or momentary locking in the picture. Each of the situations mentioned are cause of the consumer to search for another carrier. Each situation could have been avoided if proper attention was presented to the strategies used in planning, installing, and maintaining fiber optic cables.
Having said that, why don’t we review basic fiber preparation? Jacket Strippers are employed to take away the 1.6 – 3.0mm PVC outer jacket on simplex and duplex fiber cables. Serrated Kevlar Cutters will cut and trim the kevlar strength member directly underneath the jacket and Buffer Strippers will eliminate the acrylate (buffer) coating through the bare glass. A protective plastic coating is applied for the bare fiber after the drawing process, but prior to spooling. The most common coating is a UV-cured acrylate, which can be applied in 2 layers, resulting in a nominal outside diameter of 250um for that coated fiber. The coating is extremely engineered, providing protection against physical damage caused by environmental elements, such as temperature and humidity extremes, contact with chemicals, point of stress… etc. as well as minimizing optical loss. Without it, the maker would be unable to spool the fiber without having to break it. The 250um-coated fiber is the foundation for many common fiber optic cable constructions. It is usually used as is also, especially when additional mechanical or environmental protection is not required, like on the inside of optical devices or splice closures. For extra physical protection and ease of handling, a secondary coating of polyvinyl chloride (PVC) or Hytrel (a thermoplastic elastomer which includes desirable characteristics to be used as a secondary buffer) is extruded on the 250um-coated fiber, enhancing the outside diameter as much as 900um. This sort of construction is called ‘tight buffered fiber’. Tight Buffered may be single or multi fiber and are seen in Premise Networks and indoor applications. Multi-fiber, tight-buffered cables often can be used for intra-building, risers, general building and plenum applications.
‘Loose tube fiber’ usually includes a bundle of fibers enclosed in a thermoplastic tube referred to as a buffer tube, that has an inner diameter that is slightly larger than the diameter from the fiber. Loose tube fiber features a space for your fibers to grow. In certain climatic conditions, a fiber may expand and after that shrink again and again or it may be subjected to water. Fiber Cables will sometimes have ‘gel’ in this cavity (or space) yet others which can be labeled ‘dry block’. You will discover many loose tube fibers in Outside Plant Environments. The modular form of FTTH Cable Production Line typically holds up to 12 fibers per buffer tube using a maximum per cable fiber count of over 200 fibers. Loose-tube cables can be all-dielectric or optionally armored. The armoring can be used to guard the cable from rodents such as squirrels or beavers, or from protruding rocks in a buried environment. The modular buffer-tube design also permits easy drop-off of groups of fibers at intermediate points, without upsetting other protected buffer tubes being routed to many other locations. The loose-tube design also helps in the identification and administration of fibers in the system. When protective gel is present, a gel-cleaner such as D-Gel is going to be needed. Each fiber will likely be cleaned with the gel cleaner and 99% alcohol. Clean room wipers (Kim Wipes) are a great option to use with all the cleaning agent. The fibers inside a loose tube gel filled cable will often have a 250um coating so that they are definitely more fragile compared to a tight-buffered fiber. Standard industry color-coding is also used to identify the buffers as well because the fibers inside the buffers.
A ‘Rotary Tool’ or ‘Cable Slitter’ can be employed to slit a ring around and through the outer jacketing of ‘loose tube fiber’. Once you expose the durable inner buffer tube, you can make use of a ‘Universal Fiber Access Tool’ which is perfect for single central buffer tube entry. Used on the same principle as the Mid Span Access Tool, (that allows access to the multicolored buffer coated tight buffered fibers) dual blades will slit the tube lengthwise, exposing the buffer coated fibers. Fiber handling tools such as a spatula or even a pick may help the installer to access the fiber in need of testing or repair. Once the damaged fiber is exposed a hand- stripping tool will be utilized to remove the 250um coating in order to work with all the bare fiber. The next phase is going to be washing the fiber end and preparing so that it is cleaved. A great cleave is probably the most essential factors of producing a low loss over a splice or perhaps a termination. A Fiber Optic Cleaver is a multipurpose tool that measures distance through the end of the buffer coating to the point where it will likely be joined plus it precisely cuts the glass. Remember to employ a fiber trash-can for your scraps of glass cleaved from the fiber cable.
When performing fusion splicing you will need a Fusion Splicer, fusion splice protection sleeves, and isopropyl alcohol and stripping tools. If you use a mechanical splice, you will want stripping tools, mechanical splices, isopropyl alcohol as well as a mechanical splice assembly tool. When hand terminating a fiber you will require 99% isopropyl alcohol, epoxy/adhesive, a syringe and needle, polishing (lapping) film, a polishing pad, a polishing puck, a crimp tool, stripping tools, fiber optic connectors ( or splice on connectors) and piano wire.
When a termination is done you need to inspect the conclusion face of the connector with Optical Fiber Proof-Testing Machine. Making sure that light is getting through either the splice or perhaps the connection, a Visual Fault Locator can be utilized. This item of equipment will shoot a visible laser down the fiber cable so you can tell there are no breaks or faulty splices. When the rhnnol light stops down the fiber somewhere, there is most likely a break in the glass in that point. Should there be over a dull light showing on the connector point, the termination had not been successful. The light should also go through the fusion splice, if it does not, stop and re- splice or re-terminate.