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Can You Splice a Fiber Optic Cable?

Splicing fiber optic cable may seem daunting. These high-tech cables need to be almost perfect to transmit data properly. And as we’ve seen personally on chaotic installs: bending them too far can actually cause them to snap and break! If you have damaged cables or need to add a length to your current ones, you may think that your only choice is to consult a professional. While this may be a good option, with a bit of know-how and practice, you can splice your own cables.

You can splice fiber optic cable. Two main methods can create an efficient splice: fusion splice and mechanical splice. Each one takes a bit of time to master correctly. While mechanical splices are easier, fusion splices incur less insertion loss.

Fiber optic cables can be tricky to work with. You need to be aware of the safety precautions necessary for this type of work. Understanding this and how to perform a proper splice, and you should be ready to work with your fiber. To further explore how this is done, let’s look at the two main types of splicing.

Options for Splicing Fiber Optic: Mechanical and Fusion Splicing

Multiple fiber optic cable pigtails

Splicing is when you join two fiber optic cables together. This is one of the main methods for joining cables but is certainly not the only one. Additionally, you can also join cables with a technique called termination or “connectorization”.

The main draw of splicing is that you often get lower light loss and back reflection than other methods like termination. Splicing is the best method when dealing with long cable runs and when joining two different types of cables together.

Of the two main splicing methods—fusion and mechanical—fusion tends to be more reliable and exact. In contrast, mechanical splices are usually easier to perform and better for beginners. The International Telecommunication Union (ITU) provides standards for both these splicing methods.

Keep in mind that both types of splicing require a certain degree of skill. Additionally, you need to be very careful when splicing cables. Not only can a small mistake cause an imperfect splice, but it can be dangerous dealing with the glass shards.

These glass shards are tiny and brittle. This means they can quickly get stuck in your skin. When they do, they are a pain to get out. Often, you may not even notice the glass stuck in you. If this occurs, you will need to seek medical attention.

If left alone, the shard may cause an infection. This is something you don’t want to deal with, so be very careful. To perform each type of splice, you will need similar tools including a Fiber Optic Cable Stripper, a Fiber Optic Cable Cleaver, and Isopropyl Alcohol Cleaning Wipes, all of which can be found on Amazon at the last 3 links.

You will need more tools and equipment depending on the type of splice you are performing. Now that you understand how delicate a procedure splicing is, let’s examine each splicing type thoroughly. 

How to Perform a Mechanical Splice

Mechanical splices are easy-to-use alignment devices. They hold the ends of fibers together precisely. This alignment allows for light to move from one fiber to the other. Additionally, the typical loss you get from this type of splice is around 0.3 dB.

The assembly is a self-contained optical junction. While they can be useful, they are not necessarily for permanent use. To perform a mechanical splice, you will need the splice housing itself. There are lots of options out there—like the Kelushi Mechanical Splice (on Amazon).

Keep in mind that some are more sturdy and efficient than others. To perform a mechanical splice, follow the steps laid out below:

  1. Prepare the cables by stripping them, being careful not to damage the inner core.
  2. Next, you will need to give the cable a good cleaning. This is a very important step as dirty fibers can cause issues with insertion loss.
  3. Cleave the fiber cores carefully
  4. Join the fibers using your mechanical splice. Do this by positions the fibers end to end inside the splice itself. 
  5. Since the splice offers protection, you don’t need to worry about covering your work. 

How to Perform a Fusion Splice

A fusion splice uses a machine—like this D YEDEMC SM&MM Splicer (on Amazon)—to perform the splice. The device can precisely align the two ends of the fibers and fuse them. It does this by using some type of heat or electrical arc. This splice’s main benefit is that it produces a connection with a very low light loss transmission (around 0.1 dB). You can see this up-close in a gif here.

To perform a fusion splice, follow the steps for the mechanical splice up until step 4. After that, you should:

  1. Place a heat shrink tubing on one end of the one cable. Use fusion specific heat shrink wrap—like these Dia Heat Shrinks (on Amazon)
  2. Place the fiber ends into the machine, making sure not to touch the recently cleaned and cleaved ends.
  3. Follow instructions for your machine. Each one may be slightly different, but essentially you will need to make sure the cleaved ends are clean and the fibers are lined up correctly
  4. Once the machine has done its work, check to make sure you performed the splice correctly. Most machines will do this for you and give you a reading.
  5. If everything checks out, you will need to remove the newly spliced cable from the machine carefully.
  6. Next, carefully place the heat shrink tubing over the splice. Make sure there is enough space on either end for a proper seal.
  7. Most fusion splice machines will have an area to heat the shrink wrap. Follow your device’s instructions for this process.
  8. If you perform everything correctly, you should now have a clean fusion splice. For a better understanding of this process, check out this video on fiber optic cable splicing.

The Easiest Method for Splicing Fiber Optic

Fiber optics single mode patch cord SC to LC connector

When it comes to splicing, each method has its advantages. Think about how often you will need to splice cables and how reliable you need your splices. Additionally, the price can play a significant factor in your decision.

For the more straightforward method, mechanical splicing takes the lead. Mechanical splicing may have a higher cost per splice (around $10-$50), but the initial investment is low. Also, this method does tend to be more friendly to beginners. The downside is that it’s less precise.

Fusion splicing, on the other hand, tends to be more expensive on the front end. A typical fusion splicing machine can run you at a minimum of ~$1000. From there, though, the cost of each splice is very cheap (around $1).

Furthermore, the splices from a fusion machine result in lower light loss. For the average person, mechanical splicing is cheaper and easier to perform. If you plan on performing a lot of splices, you may want to think about investing in a fusion splicer.

Benefits of Splicing Your Own Fiber Optic

There are plenty of benefits to splicing your own fiber optic cables including getting custom cable lengths, repairing your own cables, and also having an immediate, cost-effective solution if you’re continuously running into damaged cables.

Since fiber optic cables are made of glass, they can be damaged fairly easily. This can happen when digging with underground cables. It can also occur just by mishandling fiber optic cables. While you can always consult a professional, understanding how to splice your cables may be cheaper.

Most telecommunications professionals will indeed use a fusion splice. For certain runs, on the other hand, they may use a mechanical one. This is something you could accomplish reasonably easily, depending on the situation.

Some Drawbacks Of Splicing Fiber

We should mention, not all fiber is created equally. As some afficianados have discussed online (forum link), you can’t just splice in fiber optic wily-nilly. If yo’ure thinking you can repair a fiber issue in, say, AT&T’s line because you hit it rather too aggressively with a shovel, that’s really now how it works.

You’ll have to get in touch with them directly so they can splice it in their way. This is because splices causes degradation of the information that needs to be accounted for.

Tips For Splicing Your Own Fiber Optic Cable

If you’re going to do this a lot, or maybe just one time in a super critical install, then you should know there are some ways you can stack the odds in your fabor ahead of time. Here are our tips for making good fiber optic splices, every time:

  1. Cultivate Cleanliness: To achieve optimal results with fiber optic splicing, cleanliness is critical. Minuscule particles, although not discernible to the human eye, can introduce significant complications when working with fiber optics. Establishing a routine for meticulously cleaning your fiber optic tools and materials can prevent issues down the line and safeguard your time and financial resources. Learn to love canned air (on Amazon).
  2. Quality Cleaver – A Must-Have Tool: A fiber optic cleaver is the cornerstone of your splicing tool kit. A flawless cleave is vital for optimal light propagation, and a top-tier cleaver is indispensable in achieving this. In the context of mechanical splicing, expect to invest between $100 and $1,000 for a reliable cleaver. For fusion splicing, which demands an even greater degree of precision, you may need to budget starting at $1,000… Proper upkeep and correct usage of your cleaver, as per the manufacturer’s guidelines, will extend its lifespan and ensure peak performance.
  3. Fine-Tune Fusion Parameters with Caution: (Only applicable to Fusion Splicing) Adjusting fusion parameters should be approached with caution. Rather than tweaking these parameters impulsively at the slightest problem, first ascertain the cleanliness of your equipment. The two defining variables in splicing are the fusion time and current. Different combinations of these two parameters can deliver identical splicing outcomes. Alter one variable at a time, and continue testing until you have identified the optimal fusion parameters for your specific fiber type.

So, maybe you’re ready to start a big, custom install now that you know you can cut your fiber optic to length! It’s not a process for the faint of heart, but it’s also not rocket science. And don’t forget: once you can splice fiber optic, you’re mistakes don’t matter anymore! You can just re-splice it – haha!