How to fusion splice two optical fibers

January 23, 2019.


In this article, we will give you a brief, easy step-by-step guide about how to make two optical fiber fusion splicing. You can read it and help you with the images, or watch this video on YouTube where we explain in five minutes how the optical fiber is fused.

  1. Place the protective sleeve
  2. Remove the plastic coating of the fibres
  3. Clean the fibres with isopropyl alcohol
  4. Cutting the optical fibers
  5. Run the splicing in the optical fusion splicer
  6. Using the sleeve to protect the fusion

Place the protective sleeve

Before starting to splice the two fiber optic cables, put inside the protective sleeve one of them, so it will prevent cables detach.

Place the protective sleeve
Place the protective sleeve

Remove the plastic coating of the fibres

Optical fiber is shielded by several plastic layers that have to be removed. For this purpose, the optical fiber stripper supplies different diameter holes to rid off the plastic protection to achieve the optical fiber exposed.

To do that, this step has to be repeated for every single layer.

Hold the optical fiber stripper with one hand. With the other hand take the outside of one of the optical fiber and introduce it into the proper fiber stripper hole. Then, simply stretch out the plastic shield and get rid off it. 3 cm approx. of optical fiber will be enough.

Remove the plastic coating of the fibres
Remove the plastic coating of the fibres
AF-003 PROMAX OPTICAL FIBRE STRIPPER

Clean the fibres with isopropyl alcohol

Removing the plastic coating will leave residues to be cleaned otherwise they will have an impact on the quality of the fusion splicing. An isopropyl alcohol wipe is used because this kind of alcohol evaporates very quickly without leaving residue.

Clean the fibres with isopropyl alcohol
Clean the fibres with isopropyl alcohol
PROMAX AF-004 ISOPROPYL ALCOHOL CLEANING WIPES KIT

Cutting the optical fibers

In this process we are using a precision cutter that performs a perfect 90 degrees cutting angle, which could not be achieved using other tools such as scissors. Set and secure one of the fibers so that when cutting it you have from 12 to 17 mm of exposed fiber (0.5 to 0.7 inch) after the plastic coating (step 1). This measurement is subject to the specifications of the fusion splicing machine used in the next step.

Lower the cover (step 2) and spread the blade to cut the fiber (step 3). Then, repeat this process with the other fiber.

Cutting the optical fibers with a precision cutter
Cutting the optical fibers with a precision cutter
FIBRE OPTICS CLEAVER AF-001

Remember to waste the fiber remains in a container because the fiber is a glass wire that may cause puncture accidents in fingers, eyes or other body parts both of the operator and of third parties.

Run the splicing in the optical fusion splicer

All you have to do is put in place the ends of both fibers in their corresponding guides in the optical fusion splicer. The ends of the fibers must be:

  • Aligned with each other.
  • Centered on the electrodes.

... Avoiding any physical contact between neither fibers nor electrodes. At this point, we must lower the cover of the fiber optic splicer and press the fusion key. The fiber optic splicer is a highly automated device that evaluates and aligns the fibers before proceeding to “burn” the ends using an electrical shock so that they finish up by being physically joined as if they were a single wire.

Running the fusion
Running the fusion

If the fusion splicer has interrupted the process, it may be because one of the following problems:

  • Bad arrangement of the wires on their guides.
  • The fibers are not cut at a 90 degree angle.
  • There are remains of the plastic cover on the end of the fiber.

It the fusion has been OK, the device itself will estimate the fusion losses. Otherwise, check the proper execution of the steps above.

PROMAX OPTICAL FIBRE FUSION SPLICERS

Using the sleeve to protect the fusion

At this point the two fibers have become one. Extract the fibers from the guides of the splicer and cover the fusion point with the protective sleeve. Then, insert the whole assembly into the fusion oven built into the splicer and press the proper key of the machine.

Protecting the fusion with the heat shrink sleeve
Protecting the fusion with the heat shrink sleeve

The oven will apply heat for a few seconds and the heat shrink plastic will shrink up to cover, encapsulate and thus protect the fiber.

END OF THE FUSION SPLICING TUTORIAL

From now on it is possible to work with the optical fiber cable having no fear it may break up by the point of fusion.

Done! This is the end of the optical fiber fusion splicing tutorial
Done! This is the end of the optical fiber fusion splicing tutorial.
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PROMAX is a leading manufacturer of test and measurement systems, broadcast and TV signal distribution equipment. Our product lines include measuring instruments for cable TV, satellite TV, broadcast, wireless and fibre optics networks, FTTH and GPON analyzers. DVB-T modulators, IP streamers or IP converters (ASI, DVB-T) are among the company’s latest developments.