Home Current Events The evolution of fusion splicers: from bulky lab equipment to SMART splicers

The evolution of fusion splicers: from bulky lab equipment to SMART splicers

by Jose Manuel Enriquez

By Jose M. Enriquez

On a recent call with Lucas Mays, product manager for fusion splicing equipment at AFL, he offered us some insights into the evolution of fusion splicers, one of the most vital pieces of equipment to build a reliable fiber optic network, whether it is an FTTH Network, within a Data Center, in 5G/6G or small cell applications—such as DAS—in congested/populated areas like a stadium or concert hall.


Splicing means joining two ends of the fiber, either mechanically, through connectors, or through a fusion process that permanently joins the fibers. According to the Fiber Optic Association (FOA), “Fusion splicing is most widely used as it provides for the lowest loss and least reflectance, as well as providing the most reliable joint”.

The early days

The first fusion splicer was developed by Fujikura in 1977 (see Fujikura Odyssey, Vol. 02 for a more detailed account of how splicing equipment came to be).

“In 1979, this equipment was sent to an exhibition attached to the Optical Symposium in Washington D.C. It was just a small space in a corner of the exhibition hall, but our exhibition was noticeable by the crowds of visitors in front of our booth” – Fujikura Odyssey, Vol. 02

Fusion splicing of fibers was a challenging task that required bulky equipment, a microscope, and very skilled technicians.

“That Fusion Splicer was about as manual as it gets, the machine was just a static, electromechanical, piece of equipment. It was a device that you physically had to turn mechanical dials to move the fibers towards one another, and then through a microscope view the fibers. There were no cameras, no magnification, just a single set of lenses and a button that you pressed to start the process. And then, even once you did that, you’re splice loss would probably still be more than 0.5 dB, and that was a good splice!” affirmed Mays.

This required a high level of skill by the technician, but also a little bit of luck and art; thus, making this a very inaccurate, not easily repeatable, process.

Fujikura FR-1, the world’s first splicer | Image Source: Fujikura Odyssey, Vol. 02

The evolution

As computer & processing technology evolved, they were incorporated into this type of equipment, and more functions and skills started being taken away from the user, reducing room for error and providing more reliable results.

Today, the technician’s job, depending on the type of splicer you are using, is more about the preparation process: removing the cable jacket & loose tube, cleaning gel from fibers, making sure the individual fibers are stripped, cleaned, and cleaved properly, etc. From there, the splicer takes over; the splicer’s image processing and automated alignment mechanisms ensure a quality splice is repeatedly produced without the operator touching the machine until the newly spliced fiber is ready to be removed from the fusion splicer.


According to Mays, aside from the quality of your splicing equipment, perhaps one of the most critical factors to a proper fusion splice is the cleanliness of the whole process. How clean the cleavers, v-grooves, and the area where you operate, will have an impact on your results.

Variety of fibers, fiber assemblies, and cables
Back in the day, there was primarily one type of fiber and few cable designs; while today, we have a large variety of cables, fibers, and fiber assemblies.

We can choose between lose tube cables or tight buffer, gel-filled or gel-free, micro cables, ribbon & flexible ribbon cables, bend insensitive fibers (ITU.G.657) vs standard single mode fibers (ITU.G.652), and then 200 µm vs 250 µm fibers, just to name a few; so, while fusing splicing technology has made the splicing process easier, fiber and cable technology keep adding new challenges to the equipment manufacturers, making R&D a continuous, ongoing process.

“Stepping from single fiber to ribbon is a big jump. Stripping the cables is very much the same; but once you get to the splicing process, that changes quite a bit because there is a different process for preparing ribbon fiber versus single fiber. There are some different tools, particularly for stripping off the coating. You can’t use a mechanical stripper, you must use a thermal stripper, which heats the fiber coating to soften it; if you just tried to mechanically strip off the coating, chances are you would break the fibers” explained Mays.

Fujikura´s technology has advanced to make them flexible and adjust to all sorts of fibers and cables. “The v-grooves are interchangeable so that you can handle all those different flavors, and even do single fiber splicing with the ribbon splicer if you’d like to. And thus, your ribbon splicer ends up being a Swiss Army type of splicer, if you will”.

Thanks to ongoing R&D, tools and processes have continued to improve; thus, even with all the challenges brought by all these new types of fibers, cables, and cable assemblies, the technology has simplified the splicing process.

V-Groove Adapters for 200 µm y 250 µm fibers | Image courtesy of Fujikura
V-Grooves for Flexible Ribbon Cables | Image courtesy of Fujikura

SMART Splicers

We live in a world of SMART devices, and splicing equipment is not an exception. Technology and innovations have turned these pieces of equipment into highly automated “SMART” machines.

“The word SMART gets tossed around quite a bit: smartphone, smart cars, smart cities, etc… SMART gets thrown on to everything; but what does it really mean? SMART is an acronym. It stands for Self-Monitoring Analysis and Reporting Technologies,” said Mays.

The basic concept of spicing hasn’t changed much “aligning and arc welding those two fibers together has been the same for many years, but a lot of the surrounding enabling aspects to making that easier, simpler, faster, and of better quality, that’s really what’s continued to evolve”.

Modern fusion splicers are now doing things like talking to fiber preparation accessories. Mays continued: Not only are they talking, but they’re talking for the purpose of monitoring preparation quality. Every time you cleave, it’s taking that data, monitoring how good the cleave is, and when it gets to a point where it’s no longer giving you the desired cleave to make a good splice, it’s (the splicer) going to say, hey, it’s time to rotate your blade and it will then send a signal to the cleaver–which has motors inside—to actually rotate that blade for you. And so, it’s a process you no longer even think about, nor manage, whereas previously you did (or even with other manufacturers you still do).

Communication between fusion splicer & cleaver | Image courtesy of Fujikura

Today the splicers are doing a lot more, modern machines not only view the core and align it in a core alignment splicer, but also tell you what type of fiber you’re splicing as it scans the fiber it’s looking at.

“The image that you’ll see on the screen can tell you what type of fiber that it is, whether it’s multi-mode, single mode or bend insensitive fiber; and, when it recognizes these different types, it will then apply the arc parameters that are necessary to give you a good splice even if you have different types of fibers being joined. And so, that’s something—that again—is the technology of self-monitoring.

The Cloud

Analyzing, reporting, and self-adjusting are great, but since we live in a “Cloud” world, all this data can also be sent to a database that you can access from your phone.

“A mobile app can get that data anywhere, and use it, for instance, to show proof of job completion. Some people are using it to see what kind of errors they might be getting, and thus they can diagnose if there’s something wrong with the machine, or if it’s an operator-related type of error, and give them some more insights into how to best manage their equipment”.


In a world of increasingly higher fiber-count cables, having the proper splicing equipment, alongside the proper tools and a clean environment, will ensure that your network can operate at its best. It’s important that you don’t underestimate the value of these machines, they will save you time, money, and headaches, in the long run.


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