I recently watched my coworker disassembling a computer 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 is definitely more than one tool out there that would have made the work easier! This case is unquestionably 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 make use of the scissors to hack away at the Kevlar? Did you nick the glass? Did you accidentally cut through the glass and have to start over?
Correctly splicing and terminating Fiber Coloring Machine requires special tools and techniques. Training is important and there are numerous excellent types of training available. Tend not to mix your electrical tools together with your fiber tools. Make use of the right tool to do the job! Being familiar with fiber work will become increasingly necessary as the value of data transmission speeds, fiber to the home and fiber to the premise deployments continue to increase.
Many factors set fiber installations apart from traditional electrical projects. Fiber optic glass is quite fragile; it’s nominal outside diameter is 125um. The slightest scratch, mark or even speck of dirt will affect the transmission of light, degrading the signal. Safety factors important simply because you will work with glass that can sliver to your skin without being seen from the eye. Transmission grade lasers are extremely dangerous, and require that protective eyewear is a must. This industry has primarily been coping with voice and data grade circuits which could tolerate some interruption or slow down of signal. Anyone speaking would repeat themselves, or the data would retransmit. Today we are coping with IPTV signals and customers that will not tolerate pixelization, or momentary locking of the picture. Each of the situations mentioned are reason for the consumer to look for another carrier. Each situation might have been avoided if proper attention was presented to the methods used when preparing, installing, and looking after fiber optic cables.
With that being said, why don’t we review basic fiber preparation? Jacket Strippers are used to eliminate 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 beneath the jacket and Buffer Strippers will remove the acrylate (buffer) coating from your bare glass. A protective plastic coating is used for the bare fiber after the drawing process, but prior to spooling. The most common coating is actually 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 very engineered, providing protection against physical damage caused by environmental elements, including temperature and humidity extremes, exposure to chemicals, point of stress… etc. while also minimizing optical loss. Without this, the manufacturer would struggle to spool the fiber without breaking it. The 250um-coated fiber will be the building block for many common fiber optic cable constructions. It is usually used as it is, especially when additional mechanical or environmental protection is not needed, including within optical devices or splice closures. For additional physical protection and ease of handling, a secondary coating of polyvinyl chloride (PVC) or Hytrel (a thermoplastic elastomer which has desirable characteristics to be used as a secondary buffer) is extruded on the 250um-coated fiber, improving the outside diameter as much as 900um. This sort of construction is known as ‘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 as intra-building, risers, general building and plenum applications.
‘Loose tube fiber’ usually consists of a bundle of fibers enclosed in a thermoplastic tube referred to as a buffer tube, that has an inner diameter that is slightly greater than the diameter from the fiber. Loose tube fiber features a space for that fibers to grow. In certain climate conditions, a fiber may expand then shrink again and again or it may be in contact with water. Fiber Cables will sometimes have ‘gel’ in this particular cavity (or space) yet others which are labeled ‘dry block’. You can find many loose tube fibers in Outside Plant Environments. The modular design of FTTH Cable Production Line typically holds approximately 12 fibers per buffer tube using a maximum per cable fiber count in excess of 200 fibers. Loose-tube cables can be all-dielectric or optionally armored. The armoring is used to guard the cable from rodents like 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 interfering with other protected buffer tubes being routed to other locations. The loose-tube design will help with the identification and administration of fibers within the system. When protective gel is found, a gel-cleaner including D-Gel will likely be needed. Each fiber is going to be cleaned with the gel cleaner and 99% alcohol. Clean room wipers (Kim Wipes) are a great decision to use using the cleaning agent. The fibers inside a loose tube gel filled cable normally have a 250um coating therefore they are more fragile than a tight-buffered fiber. Standard industry color-coding is additionally used to identify the buffers as well as the fibers in 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 utilize a ‘Universal Fiber Access Tool’ which is made for single central buffer tube entry. Used on the same principle because the Mid Span Access Tool, (that allows accessibility multicolored buffer coated tight buffered fibers) dual blades will slit the tube lengthwise, exposing the buffer coated fibers. Fiber handling tools like a spatula or even a pick may help the installer to get into the fiber looking for 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 thing is going to be washing the fiber end and preparing so that it is cleaved. An excellent cleave is one of the most important factors of making a low loss on the splice or a termination. A Fiber Optic Cleaver is really a multipurpose tool that measures distance from your end of the buffer coating for the point where it will likely be joined plus it precisely cuts the glass. Never forget to use a fiber trash-can for that scraps of glass cleaved off of the fiber cable.
When performing fusion splicing you might 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 along with a mechanical splice assembly tool. When hand terminating a fiber you will need 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.
Whenever a termination is complete you must inspect the final face from the connector with Optical Fiber Proof-Testing Machine. Making sure that light is to get through either the splice or perhaps the connection, a Visual Fault Locator can be applied. This item of equipment will shoot a visible laser down the fiber cable which means you can tell that we now have no breaks or faulty splices. In the event the rhnnol light stops down the fiber somewhere, there is probably a break within the glass at that point. When there is over a dull light showing in the connector point, the termination had not been successful. The light must also move through the fusion splice, if this will not, stop and re- splice or re-terminate.