Fusion Splicing 101: A Brief Introduction

Fusion splicing is the most widely used technique, the objective of which is to achieve such a join where light passing through the fiber is not scattered nor reflected back. In this article we will briefly describe fusion splicing, why it is preferred over mechanical splicing, and at the end, some of its advantages over mechanical splicing will be discussed. Before we dig any further, these are the two types of optic fiber splicing:

  1. Mechanical splicing
  2. Fusion Splicing

Mechanical Splicing

Mechanical splicing is not a permanent solution as this method contains various insertion losses as well as back reflection; it is mostly used for emergency situations where immediate repair is needed. In mechanical splicing two fibers are not joined physically rather they are held inside a sleeve where their two ends are precisely aligned so that light can pass from one fiber to another without any difficulty; in other words, we can say that mechanical splicing is simply an alignment mechanism.

Fusion Splicing

Fusion splicing has been around for decades but still it remains the most commonly used method for permanently fusing the ends of fibers. Fusion splicing is a permanent technique of joining two ends, but on the other hand, fiber connectors are easily reconfigurable.

Fusion splicing is the process in which we can fuse or wield two optical fibers end to end using a machine which precisely align the two glass fibers and then wielded the ends together generally by an electric arc or laser. Fusion splicing provides minimum reflectance and loss and the join it produces is most reliable and strongest. The required goal needs to be achieved in such a way that the light passing through the fiber is not reflected back or scattered and also the region surrounding the fiber is as strong as virgin fiber itself.

The fusion splicer equipment contains two fixtures which are used to mount the fibers and two electrodes; for heating purposes, as well as a microscope can be used so as to achieve good alignment of the two fibers end.

Splicing two ends of the optic fiber is a precise process without any error whatsoever.

Fusion splicing is mostly done on single mode fiber but on various occasions, where required, it can be applied on multimode fiber too.

Steps for a proper fusion splice:

  1. Strip all the protective coating such as tubes, jackets, etc. leave only the fiber.
  2. In this step, fiber needs to be cleaved properly, clever is required here for a good precise splice. The cleaved end needs to be smooth and perpendicular to the axis so as to achieve proper splice.
  3. The next step is alignment of the two fibers to be joined; it can be manual or automatic. In automatic alignment equipment may be used.
  4. After alignment heating is done, fusion splicer unit uses an electric arc to melt the fiber and permanently joined the two ends of the fiber.
  5. Finally after heating, it is required to protect the fiber from outside elements and to ensure that the splice will not break in future, so in order to secure the fiber we use protectors like heat shrink tubing or silicone gel across the fiber.

 Fusion Splicing Usage at Data Warehouses

We live in the age of science, every second an enormous amount of data is generated by sensors, social networking sites like twitter, facebook etc, also advancement in the field of internet of things (IoT) also becoming a reason for this bulk amount of data, with that much data the need for data warehouses is increasing day by day which in turn also resulted in more and more cables and connections than ever.

To cope with this problem we need solutions which will take less pathway space such as multi fiber cables. Since very few manufacturers propose field installable MTP/MPO connectors, many companies are selecting either multifiber trunk cables or fusion splicing to preterminated MTP/MPO.

Fusion splicing provides connections which have very low loss of signal, there are numerous advantages over competing technologies also currently used hand held fusion devices are very affordable and at the same time provides better features.

Two Advantages Fusion Splicing Has Over Mechanical splicing


Fusion splicing costs more upfront because we need to purchase fusion splicing machine which is somewhat costly but in terms of variable cost per splice it offers a great deal, whereas mechanical splicing doesn’t cost more upfront but it has a higher variable cost per splice.

In past, companies are reluctant to use fusion splicing technique due to its higher upfront cost but in recent years, we saw that cost associated with splicing tools are drastically decreased and now more and more people are coming towards fusion splicing technology than before.


The typical insertion loss in fusion splicing is <0.1 dB, therefore it provides better defense against weak signals and cable failures, whereas in mechanical splicing typical insertion loss is much higher than fusion splicing, it is usually between 0.2 dB and 0.75 dB because in this type of splicing the two fibers are just aligned with each other not physically joined.

To Sum it Up

In this article, we discussed some key points related to fusion splicing. In this era of science, fusion splicing plays an important role in the field of splicing because it gives low back reflection and also the join it produces is quite strong and permanent as compared with its competitors. So, at the end, we can say with confidence that whenever there is a requirement for permanent fiber join we should go for fusion splicing without thinking twice.


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