Fiber Optic Splicing

Fiber optic splicing is one of the fiber optic terminations which creates a permanent joint between the two fibers. With the benefits of low light loss and back reflection, fiber optic splicing is a preferred method when the cable runs are too long for a single length of fiber or then joining two different types of cables together. There are two methods of splicing, fusion splicing and mechanical splicing.

Fusion Splicing

In fusion splicing (as following picture), a machine called fusion splicer is used to precisely align the two fiber ends. Then the glass ends are “fused” or “welded” together using some type of heat or electric arc. This produces a permanent connection between the fibers enabling very low loss light transmission (Typical loss: 0.1 dB). Fusion splicing has the best return loss performance of all the mating and splicing techniques.

fusion-splice

Fusion Splicing Steps
    • Prepare the fiber. Strip the protective coatings, jackets, tubes, strength members, etc. and only leave the bare fiber showing. Please pay attention to keep the fiber clean.
    • Cleave the fiber. Choose a good fiber cleaver. The cleaved end must be mirror-smooth and perpendicular to the fiber axis to obtain a proper splice. But the cleaver is not used to cut the fiber. It’s only used to produce a cleaved end that is as perpendicular as possible.
    • Fuse the fiber. Align the fusion splicer unit and use an electrical arc to melt the fibers, permanently welding the two fiber ends together. Alignment can be manual or automatic.
    • Protect the fiber – To ensure the splice not break during normal handling, you must protect the fiber from bending and tensile forces. A typical fusion splice has a tensile strength between 0.5 and 1.5 lbs and will not break during normal handling but it still requires protection from excessive bending and pulling forces.
Mechanical Splicing

Mechanical splicing (as following picture) aligns and mates the end face of two cleaned and cleaved fiber tip together. It’s a reusable splice. The mechanical splice will have an index matching fluid that eliminates the fiber-to-air interface, there by resulting in less back reflections. Mechanical splices are often used when splices need to be made quickly and easily.

mechanical-splicing

Mechanical Splicing Steps
  • Prepare the fiber. Strip the protective coatings, jackets, tubes, strength members, etc. and only leave the bare fiber showing. Please pay attention to keep the fiber clean.
  • Cleave the fiber. This one is the same to the fusion splicing step. But the cleave precision is as critical.
  • Mechanically join the fibers. This method doesn’t use heat. Simply put the fiber ends together inside the mechanical splice unit. The index matching fluid inside the mechanical splice apparatus will help couple the light from one fiber end to the other. Older apparatus will have an epoxy rather than the index matching fluid holding the cores together.
  • Protect the fiber – the completed mechanical splice provides its own protection for the splice.
Which One Should You Choose?

To decide which fiber splicing method you should choose, you may take two important factors into consideration. First, it’s the cost. Mechanical splicing has a low initial investment ($1,000—$2,000) but costs more per splice ($12-$40 each). While the initial investment is about at least $15,000 and per splice cost is about $0.50 – $1.50. Second, it’s the performance. Fusion splicing offers a high degree performance of lower loss and less back reflection than mechanical splicing.

By the comparison of the cost and performance of two methods, now you know which one is suitable for your applications. If you have enough money and need more precise alignment for lower loss, you could buy a fusion splicing machine. If you just have a small budget and should make a quick splice, then you can choose mechanical fiber optic splice.

Originally published at http://www.china-cable-suppliers.com/fiber-optic-splicing.html

Make the Right Choice of Splicing

Fiber splicing is used to permanently join two optical fibers where no additional changes are expected to be made to those fibers at that juncture. Compared with joints by connectors, fiber splicing typically results in lower light loss and back reflection.

There are two methods of fiber optic splicing: fusion splicing and mechanical splicing. Both of the two are functioning the same. However, they have their own advantages and disadvantages, which should be acknowledged before choosing of the methods of splicing which best fit the economic and performance objectives.

Fusion Splicing VS. Mechanical Splicing

The following text will make a comparison between mechanical splicing and fusion splicing from several aspects (process, time requested, performance and cost) to find the best choice of splicing.

The biggest difference between mechanical splicing and fusion splicing can be figured out by their literally meaning. Mechanical splicing is mechanically joining the fibers ends together which is quick and effective. While fusion splicing is a method of fusing fibers together using arc welding which is fairly complex and requires much more skill than mechanical splicing.

Process: The first three steps of mechanical splicing and fusion splicing before connecting the fibers ends are generally the same.
  • Step one: strip the protective coatings, jackets, tubes, strength members, etc. leaving only the bare fiber showing.
  • Step two: cleave the fiber with a fiber optic cleaver. The cleaved end for fusion splicing must be mirror-smooth and perpendicular to the fiber axis to obtain a proper splice. As to mechanical, the cleaving process is identical to the cleaving for fusion splicing but the cleave precision is not as critical.
  • Step three: clean the fiber.
  • Step four: after cleaning the fiber, the connecting step starts.
    For fusion splicing, fusing fiber contains alignment and heating. Once properly aligned the fusion splicer unit then uses an electrical arc to melt the fibers, permanently welding the two fiber ends together.
    Mechanical splicing does not need heating. Simply position the fiber ends together inside the mechanical splice unit. The index matching gel inside the mechanical splice apparatus will help couple the light from one fiber end to the other.
  • Step five: protect the fiber
    Fusion splicing—using heat shrink tubing, silicone gel and/or mechanical crimp protectors will keep the splice protected from outside elements and breakage.
    Mechanical splicing—the completed mechanical splice provides its own protection for the splice.

fusion-splicing-tools

Time Requested: mechanical splicing is fast and effective, which is suitable for some emergency situations. However, fusion splicing is more skilled and need more time to be finished.

Performance: with mechanical splicing, the fibers usually have loss of 0.3dB. However, with fusion splicing, the fibers generally have a loss of 0.1dB and the fiber splices are usually stronger.

Cost:mechanical splicing has a low initial investment ($1,000-$2,000) but costs more per splice ($12-$40 each). While the cost per splice for fusion splicing is lower ($0.50-$1.50 each), the initial investment is much higher ($15,000-$50,000 depending on the accuracy and features of the fusion splicing machine being purchased). The more precise you need the alignment (better alignment results in lower loss) the more you pay for the machine.

Many companies now invest fusion for networks, especially for long haul single-mode networks. However, they also use mechanical splicing for shorter, local cable runs. Consider the requests for performance quality, time, situations and the capacity of economics before choosing the fittest method of splicing.