Vlog #17 Splicing: Single-fibre vs. Ribbon

Today, we’ll be looking at the exciting subject of splicing technology. More precisely, we’ll be comparing ribbon splicing and single-fibre splicing. To tell us more about this topic, I invited my colleagues Ronny Mees, from Product Management, and Jochen Hart, a cabling expert from our Service department. Ronny, what exactly are the differences between single fibres and ribbon fibres?

Ronny Mees: Good question. The fibres are basically the same. The difference lies in the way the cable is constructed. So, in single-fibre cables or loose-tube cables, the individual fibres are guided as single fibres inside the cable. And when you continue working with them, you have to take hold of each one of them individually - each individual fibre. A ribbon cable, just as the name suggests, is a strip in which 12 or 16 fibres are located next to one another in parallel and they stay arranged in exactly the same way along the entire length of the cable. 
That means that you can work this quantity of fibres, whether it’s 12 or 16 of them, all together in a single operation. And that is exactly what you need for connections running at high bit-rates, we also talk about parallel-optic transmission, and that is, in a sense, physically reflected in this type of cable.

Jochen, you’re our man in the field. You install cables in data centres and also do a lot of splicing. What is your experience of these two different cable constructions?

Jochen Hart: Well, the ribbon structure has a massive advantage. You can connect a lot of cables in a very short time. The cable structures are significantly smaller. This means that even if a cable path is already relatively full, you can always still add a ribbon cable to it. If you look at single-fibre cables, you don’t get them with very high fibre counts. So you have significantly fewer fibres in the cable than you do with a ribbon cable. And that is why you also have the speed advantage as well as the space benefits at the cable manager. Because you can accommodate a lot more fibres in a ribbon cable than you can in a single-fibre cable.

Jochen, I see that you’ve brought two splicers with you. So today we’re going to compare ribbon splicing and single-fibre splicing and we’ll see how big the difference in the time factor between the two types is. I’m looking forward to this.

Ronny Mees: So Jochen, we’re sitting here in front of the tools of your trade. But before we get to the units themselves perhaps we can quickly show viewers the different cables that we have here today. So, if I’ve understood correctly, here we have an 8-by-12 loose-tube cable. That means that we have 8 fibre core bundles. Each consisting of 12 individual fibres. I don’t know if this can be seen very clearly on the camera, but these really are separate and perhaps you can also show the ribbon cable.

Jochen Hart: 12 ribbons with 12 fibres each. And it’s very easy to see that there are actually more fibres in this cable than there are in the simple loose-tube single-fibre cable. And the external cladding has almost exactly the same diameter in both of them.

Ronny Mees: So here there are 96 fibres and there we have 144. So what else do you have here on your table?

Jochen Hart: Here, we have everything else we need for the individual splicing operations. For example, here we have fewer tools. What we always need, of course, is alcohol for cleaning. Here, we need stripping pliers to remove the coating of the individual fibers, like the ones we can see here, so that we can strip back this acrylic coating. Here, by contrast, for the ribbon splicer, we have a special thermal stripper. This, as it were, heats the coating and then we pull the coating off. That means that we don’t need the stripping pliers. However, there is another difference. That’s because to use all this equipment, we have special holders which we have to insert in the thermal stripper, in the cutter and in the splicer. This fibre holder is a fixed component in the single-fibre splicer, it’s in there and doesn’t have to be taken out. However, it is absolutely vital for ribbon splicing.

Ronny Mees: So you have this thermal stripper. And here there is another, similar device. What is it? 

Jochen Hart: That’s the cleaver, which is used to cut the fibres before they’re inserted in the splicer.

Ronny Mees: Do we also have to do that with ribbon cables?

Jochen Hart: Yes, that still has to be done. And here, on the side, there is a magnetic mount for this fibre holder, which comes out after the thermal stripper and is inserted in this cleaver.

Ronny Mees: Then we have the two splicers. They are the larger boxes here in the background. They look very similar. What are the differences between them?

Jochen Hart: The main differences lie in the way the fibres are guided and held. The fibre holders in the ribbon splicer are removable. You take them out in order to allow the process to run. In the single-fibre splicer, they are built-in. You don’t usually need to take them out. That’s the main difference. Apart from that, they belong to the same series and can more or less do the same thing, except that one splices single fibres and the other ribbon fibres.

Ronny Mees: Okay, so how is the splicing operation performed? What would you do first and what are the individual steps up to the point where the splice connection is complete?

Jochen Hart: Here we’ve already made a start. The first thing we did was to strip the individual cables. I’ve prepared an example here because it takes quite a long time. What is more, the process is absolutely identical for both types of cable. That means you remove the outer cladding and the rodent protection from both cables until you get to the bundled fibres or the individual fibres. You strip it all to the length you need, for the amount that has to go into the splice boxes. And then you remove the coating from whichever cable. That’s either for the ribbon or for the individual fibre. Then comes the cleaning. Then it is placed in the cutter. This cuts it to an angle of exactly 90 degrees. And then you place it in the splicer and splice it all. When you use the ribbon splicer, you must also remember to apply the shrink-on splice protection. That’s something you don’t need with single-fibre splicing. In that case, we use crimped splice protection which we apply later, after the splicing operation. That’s the usual way in Germany, Austria and Switzerland. Overseas, shrink-on splice protection is often used. However, it’s very unusual to do that in Europe.

Ronny Mees: And after that, these splices are placed in a splice cassette so that everything is properly protected.

Jochen Hart: Exactly.

Ronny Mees: To be on the safe side, our product range contains splice cassettes for both cable variants, for both splicing variants.

Jochen Hart: Precisely. 

Ronny Mees: Good, I’m looking forward to you showing us exactly how that works.

Jochen Hart: The cutting wheel and the cutting height can be adjusted using a motor. If the splicer detects poor-quality cuts, then the cutter automatically readjusts itself. And it’s exactly the same with the thermal unit, the stripper. Here, you can set the heating programs etc. in exactly the same way. That’s why they are connected via Bluetooth.

Thank you very much Ronny and Jochen for this fascinating glimpse of what goes on in the splicing process for single fibres and for ribbon fibres. I’ve learned a lot. Even though you see it again and again in data centres, you sometimes don’t pay very much attention when you’re simply hurrying past. But I found it really interesting to see all the details of how splicing works. Thank you very much for taking the time to be with us.

More information about splicing you can find here.