Fibre-Optic-Splicing-Explained

In order to join two fibres together, you will need some pretty special tools.

There are two ways to achieve a joint of two fibres; either

1/ Mechanical Splice or

2/ Fusion Splice.

Let's have a look at both these options in more detail.

A mechanical splice is achieved by using a fixture that aligns and holds the fibres in place. These are fitted with index matching gel or adhesive to match the glass so that losses remain minimal.

The quality of the fibre end has an enormous impact on the loss of the contacting points.

As you can imagine just putting broken glass fibre ends in a fixture together without cutting them would create some issues, as the fibre ends would not meet perfectly, which is not ideal.

You need to prepare the fibres with a cleave tool, specifically designed for cutting the fibres so that they are perfectly flat and smooth. Most Cleave tools have a small bin attached that catches the broken fibre ends and stores them safely for removal later.

Once you have cleaved the fibres you can place them into the mechanical splice, until they are aligned correctly, and finish by securing them in place. You must clean, cleave and load each fibre individually.

The only issue is that you do not really know the status of the cleave as you can not actually see it to approve or to fail it. So you are placing all your trust in the precision and accuracy of the cleave tool.

In most cases this will not be a concern, however, if you have damaged the cleave blade at any stage, you may not even know, and you could be producing poor quality mechanical splices. This will most likely be picked up when testing but you will have already spent a lot of time producing low-quality connections, which is not so ideal!

Other than a mechanical splice, we can do a Fusion Splice where a machine takes over and joins, welds, and tests the splice for us. 

All we need to do is prepare the fibres for splicing.

So, in this blog, we will look at the Fibresales F-7 Fusion Splicer and see how this machine works by going through some of the quick setup instructions.

There are two ways of powering up the F-7 Fusion Splicer;

• either by using the internal battery or
• by using the AC power supply.

For remote locations where there may not be power, running it on battery may be the only choice.

Start by turning the splicer on by pushing the "Power Button"

The windproof cover is there to ensure no dirt or dust is blown into the machine, which may cause issues with the splice.

They say it is a good idea to turn the unit on for a while before using it, to allow the machine to adjust to the temperature it will be operating in.

Whilst the machine is adjusting there are a few parameters that we can set up during this waiting period.

You need to decide;

1/ Splice mode - either AUTO or Manual and 

2/ Fibre Type - the choices here are SM/MM/NZDS/ED

• SM = Singlemode
• MM = Multimode
• NZDS = Non-Zero Dispersion-Shifted,NZDS fibers are fabricated with more complex physical profiles than standard single-mode fiber.NZDS fibers are more inherently more sensitive to splicing due to their more complex physical design. The end angle of the cleave, splicing equipment, and clean splicing conditions, are all critical parameters to achieving consistently low splice loss
  
• ED = Erbium-Doped, Erbium-doped fibers, deployed in erbium-doped fiber amplifiers (EDFA), often have small mode diameters (about 4-6 /spl mu/m). If these fibers were to be abruptly interfaced with larger mode field diameter (7.5-10.5 /spl mu/m) dispersion-shifted or conventional fibers, unacceptably large transmission loss penalties would be incurred.

We tend to only use only Singlemode and Multimode in the field, so that makes operations fairly simple.

Now on to loading the fibres into the Splicer;

Step 1） Open the wind protector;

Step 2） Open the left and right sheath clamps;

Step 3） Put the stripped fiber in the V-groove. And make sure that the cleaver length is set as per the operators’ intended length; Typically to suit either a 40mm or 65mm heat sleeve.

Special Note: Make sure you have the fibre protection sleeve fitted on one side of the loaded fibres to be spliced, otherwise you will have to start again! This Shrink Sleeve is what ultimately gives the splice its strength and protection.

Step 4）Ensure that the fiber is put in the V-groove correctly, then close the sheath clamps carefully. If the fiber is not properly set you will need to adjust it again. The machine will prompt you if not correct.

Step 5） Repeat the steps for the second fiber;

Step 6） Close the wind protector

You are now ready for splicing;

For  "Full auto mode," it is as easy as loading the prepared fibres and closing the windshield - the splicer will automatically begin to fuse the fibres.

This is when the magic happens. The motors drive the fibres together so they can be fused. This is also the stage where you can inspect the cleaved ends as well, to ensure they are perfect. As mentioned previously this check is missing when completing a mechanical splice.

One further suggestion would be to always do a Stretch test. What this means is that the motors will pull back on the spliced fibres, if they break the splice was not successful.

It is better to happen now rather than after installation, right? At least you get the chance to fix it before it becomes a real problem!

This can be set permanently by changing it in "Other Config: from OFF to ON (Highly recommended)

All that is left to do is to heat the fibre shrink sleeve over the bare spliced fibres for that much-needed protection ;

Step 1) Take out the fused fibre by opening the wind protector and clamps,

Step 2) Gently move the fibre protection sleeve over the fused fibres and into the centre of the heater,

Step 3) Close the heater cover,

Step 4) Press the HEAT Button (indicator light will come on),

Step 5) Once the light goes off the heating is finished and the slice can be removed.

Step 6) Allow the protection sleeve to cool down in the cooling tray.

You have now successfully completed a fusion splice in its entirety.

Conclusion;

Splicing is as easy as following some simple steps.

Having the proper equipment goes a long way to making your splicing easy, quick, and efficient.

The most important part of any splice is the cleave, without a good cleave you will not achieve a good splice result!