How to Properly Fuse Together Fiber Optic Cables

Fiber optic splicing is the process of joining two or more fibers together. Whether you’re deploying a new fiber optic network or expanding an existing network, you must ensure your fibers are properly spliced to avoid network disruptions.

Splicing fibers is commonly used to rejoin fiber optic cables when accidentally broken or to fuse two fibers together to create a fiber that is long enough for the required cable run.

There are two accepted methods of splicing fibers:

Mechanical splicing

Fusion splicing

Of the two methods, a mechanical splice can be performed much quicker than a fusion splice. A mechanical splice is a junction of two or more fibers that are aligned and then held together by connectors.

Although easier to perform, mechanical splicing allows an increase in insertion loss. So, mechanical splicing is only ideal for quick or temporary restoration, not for permanent splices.

The most common method of splicing fibers together is fusion splicing, which permanently fuses fibers together using an electric arc. This method is far more popular than mechanical splicing because it provides the lowest loss, less reflectance and the strongest joint between the fibers.


Fusion splicing is a very delicate process. If not properly done, your fibers may not be properly connected and your signal may suffer.

When performing a fusion splice there are generally five different steps:

1. Stripping the fiber

To start fusing your fibers together, you must remove or strip the protective polymer coating around the optical fiber. This is usually done with a mechanical stripping device, similar to a pair of wire strippers. Remember to clean the stripping tools before you start the fusing process.

2. Cleaning the fiber

After the fiber has been stripped of the coating, it’s time to clean the bare fiber. Using a 99.9% isopropyl alcohol (IPA) and lint-free wipes will keep the glass free of any contaminations.

3. Cleaving the fiber

A good cleaver is crucial to a successful fusion splice. The cleaver nicks the fiber and pulls or flexes it to cause a clean break rather then cut the fiber, which makes the end-face flat and perpendicular to the axis of the fiber.

4. Fusing the fiber

After the fibers have been cleaved, fuse them together with a fusion splicer. First, you must align the ends of the fiber within the splicer. Once properly aligned, melt the fibers with an electric arc, permanently welding the ends together.

5. Protecting the fiber

After the fibers have been successfully fused together, the bare fiber is protected either by re-applying a coating or by using a splice protector.


Don’t forget to test the fiber after it’s been fused. Using an optical time domain reflectometer (OTDR) helps verify the splice loss, measure the length and find any faults in the spliced fiber.

Fiber cable is delicate and must be handled with care. One bad splice is all it takes to cause attenuation on your fiber optic cable, diminishing the quality of your data transmission or even creating a costly network outage.

Author: Fiber-MART.COM

eShop of Fiber Optic Network, Fiber Cables & Tools

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