Factory-Made In The Field

Last month, I addressed how to determine if an adhesive/polish connector was good by inspecting the polished end of the connector with a microscope. If the polished end of the connector ferrule looks smooth and does not have scratches or cracks, it’s highly likely the connector has been properly made and will be low-loss.

How do you achieve a good, polished finish on the connector? Factories work in a clean indoor environment, have trained personnel who do some of the assembly work by hand, and polish with machines according to carefully devised programs. They get very consistent, well-polished, low-loss connectors. How can the average field installer do equally acceptable work?

Let’s start with the clean environment. If you are working on a dirty or dusty construction site, you will have trouble keeping airborne dust from scratching the connector end-faces during polishing. If possible, wait until construction is finished and the site has been cleaned up. If you must do it in the midst of construction, use plastic drop cloths to wall off the area and keep out dust or even use one of those outdoor tents that outside plant (OSP) splicers use.

Second, get trained. I don’t care how easy the sales literature and salesperson says it is because that isn’t the case. Spend a few hours with someone who actually knows how to do the termination. A good choice of expert might be a trainer for a fiber optics school or someone who works for a manufacturer or distributor. From that person, you will learn the basics and some of the tricks you need to know to make it easier. Don’t let anybody fool you; every connector offers some tricks to the termination process.

Get a set of tools and testing equipment, a quantity of connectors, the proper adhesive, and various types of cables, and then practice, practice, practice. You have probably heard that it takes 10,000 repetitions to become a master of a process, but by 50–100 or so, you will be at least 90 percent of the way there. Get a buddy to practice with you. You can learn from each other’s mistakes—and you will inevitably make mistakes.

With a good microscope, inspect every connector you make, and test it with a light source and power meter. Otherwise, how will you know how good your connectors are?

Use only the types of adhesives reliable sources recommend. No Krazy Glue, epoxy from the hardware store, etc. Just use the correct adhesive, and ensure it is fresh. Out-of-date adhesives may not cure properly and/or may have low strength bonds between the fiber and the ferrule.

Before you get started, set up your workspace. It’s best to work on a black mat because it helps you see the fiber. You can purchase black mats from fiber optic suppliers, or make one with black vinyl that you can buy at a fabric store. Place all the tools and supplies you need within easy reach. If you are left-handed, ensure the tools you choose are appropriate for lefties. Some strippers are especially bad for left-handed people, making it hard to strip the fibers without breaking them. Also, ensure you have good lighting. If you have a problem in the field, get a battery-powered light-emitting diode (LED) light or two.

Once you have your work area organized, it’s time to put on safety glasses and practice the process. If you are using heat-cured epoxy or Hot Melt connectors, start your oven heating well before you begin. Open a connector package, and spread out the components. There should be a connector body (and a snap-on cover, if it’s an SC), a crimp sleeve, and a protective cap (often called a “dust cap,” not because it keeps the connector from getting dusty but because the caps are usually full of dust) which gets on the connector.

If you are using a simplex cable with strength members, begin the process by sliding a strain-relief boot over the cable followed by the crimp bushing. On plain tight buffer fiber, you just slide on the correct boot. If you are terminating a loose tube cable, you will need to install a furcation kit. It’s a complex, delicate and time-consuming process, but once you do it, you will understand why these cables are usually terminated by splicing on pigtails.

Now you are ready to prepare the fiber, except I’m out of space. Next month, I’ll discuss the actual process of installing the connector on the end of the fiber.

About the Author

Jim Hayes

Fiber Optics Columnist and Contributing Editor

Jim Hayes is a VDV writer and trainer and the president of The Fiber Optic Association. Find him at www.JimHayes.com.

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