What is fiber optic cable splicing?

Fiber optic cable splicing, briefly speaking, is the joining of two cables together, or a technology that join two different fiber optic cables together. This technology is mainly involved in the telecommunication industry, LAN and various networking projects.

How to join the fiber optic cable?

When fiber optic cable splicing is required, there are two methods called mechanical splicing and fusion splicing. These two methods of splicing will cause different economic costs and performances, so knowing the details of each methods is pretty vital for making the best choice for your goal between these two techniques.

Fusion splicing

This method is also called permanent connection of fiber optic cables. In this way two or more fiber optic cables will be permanently joined by welding using an electronic arc. It requires a precise cleaver machine to doing alignment of the ends of fiber optic cables, which enable the cable deliver a very low loss light transmission.

Mechanical splicing

This method is by holding two fiber optic cables’ ends in a precisely aligned point by alignment device to mechanically join the cables together. In this technique, a fusion splicer is not required, which is the difference between mechanical splicing and fusion splicing. Mechanical splicing is considered a more efficient method, there is no heat involved while the light loss increases in transmission.

All talked above also belongs to fiber optic cable connecting. While fiber optic cable connecting is not equal to but means more than fiber optic cable splicing. Fiber optic cable connecting includes connecting the two or more different cables by direct contact such as fusion splicing and mechanical splicing, or indirect contact by various fiber optic connecting components like fiber optic transceiver. This connection is commonly used in the network cabling in buildings due to its convenience, reliance and flexibility.

Types of Splicing

There are 2 methods of splicing, mechanical or fusion. Both methods provide much lower insertion loss compared to fiber connectors.

Mechanical Splicing

Fiber optic cable mechanical splicing is an alternate splicing technique that does not require a fusion splicer.

A mechanical splice is a junction of two or more optical fibers that are aligned and held in place by an assembly that holds the fiber in alignment using an index matching fluid. Mechanical splicing uses a small, mechanical splice, about 6cm long and 1cm in diameter that permanently joins the two optical fibers. This precisely aligns two bare fibers and then secures them mechanically.

A snap-type cover, an adhesive cover, or both, are used to permanently fasten the splice.

The fibers are not permanently joined, just precisely held together so that light can pass from one to another. (Insertion loss < 0.5dB)

Splicing loss is typically 0.3dB. But fiber mechanical splicing introduces higher reflection than the fusion splicing method.

Fiber optic cable mechanical splices are small, quite easy to use, and are very handy for either quick repairs or permanent installations. They are available in permanent and reenterable types.

Fiber optic cable mechanical splices are available for single-mode or multimode fibers.

Fusion Splicing

Fusion splicing is more expensive but has a longer life than mechanical splicing. The fusion method fuses the fiber cores together with less attenuation. (Insertion loss < 0.1dB)

In the fusion splicing process, a specialized fusion splicer machine is used to precisely align the two fiber ends then the glass ends are “fused” or “welded” together using an electric arc or some type of heat. This produces a transparent, non-reflective and continuous connection between the fibers enabling very low loss light transmission. (Typical loss: 0.1 dB)

The fusion splicer performs optical fiber fusion splicing in two steps.

1. Precisely align the two fibers

2. Generate a small electric arc to melt the fibers and weld them together

With proper training, a fiber splicing technician can routinely achieve less than 0.1dB insertion loss splicing for both single-mode and multimode fiber cables.

In addition to lower splicing loss at 0.1dB typical, advantages of fusion splicing include less back reflection.

The common application for splicing is jointing cables in long outside plant cable runs. This is where a length of a run requires more than one cable. Splicing is generally used to terminate single-mode fibers (by splicing pre-terminated pigtails onto each fiber) but there are other uses. It is important to note that slicing can be used to mix different types of fiber cables like connecting 48 fiber cables to six 8 fiber cables going to different places.

Advantages of Mechanical Splicing:

1. Mechanical splices do not require electricity.

2. Other than a fiber stripper and a fiber splitter, many mechanical fiber splice designs require no additional equipment.

3. Mechanical splicing is useful in cases where fusion splicing is not conceivable or practical. This makes them perfect for short-term connections.

Disadvantages of Mechanical Splicing:

1. The insertion loss is much higher. The normal insertion loss of a mechanical splice is about 0.2 dB, which is much greater than the 0.02 dB loss of a standard fusion splice. Multimode fibers are usually spliced mechanically.

2. Mechanical splices struggle to meet the alignment tolerances of single-mode fibers.

3. Mechanical splices are only used under relatively safe conditions, such as in an office building.

Best Practices to Perform Better Fiber Optic Cable Splicing

As with anything, practice makes perfect. And knowing some fiber optic splicing best practices can go a long way in completing better splices with minimum back reflection and maximum transmission efficiency.

Here are three easy yet effective ways to perform better splicing:

#1 – Ensure Your Splicing Tools are Clean

Considering the microscopic nature of fiber optics, know that particles not visible to the naked eye could cause huge problems in terms of cable performance.

There’s no such thing as “excessive cleaning” of your fiber optic tools, and investing some effort in keeping your splicing tools immaculate will save you a lot of time and money in the long run.

#2 – Use and Maintain Your Cleaver Correctly

The cleaver is the most valuable tool you need to complete effective fiber optic splicing.

For mechanical splicing, you must ensure the proper angle of end faces, otherwise, there’ll be excessive light escaping into the air gaps between the two fibers. Sure, an index matching gel will help minimize light escape, but the importance of a high-quality cleaver cannot be overlooked.

For fusion splicing, your cleaver plays an even more important role to achieve the incredible low attenuation of less than 0.1 dB.

Simply put, if you don’t maintain your cleaver, the fiber ends may not fuse together properly, resulting in high attenuation and back reflection.

The best way to clean and maintain your cleaver’s quality is to simply follow the manufacturer’s instructions.

#3 – Set Your Fusion Parameters in a Systematic Way

Don’t start altering the fusion parameters on the splicer whenever there is a hint of a problem, as you might lose your desired setting.

Broadly speaking, fusion time and fusion current are the two main parameters whose variables can be varied to produce strong splice results. Change only one variable at a time in a methodical way until you find the right fusion parameters for your fiber type.

Conclusion

Fiber optic splicing technology is often considered as an important training and knowledge for companies involved in telecommunication and networking as well as the fiber optic technician. This article gives ideas that are easy to understand about this technology with the expectation of getting it known accurately and helping people have better performance.