How To Install Fiber Optic Connectors

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Post on Friday 10 April, 2015
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Fiber-Mart Fiber Optic Connectors & Adapters

Fiber optic connector provides a method for technicians and end users to easily connect and disconnect an optical fiber link, without using any special tools. To complete the path between fiber optic transmitter and receiver, technicians must install connectors at both ends of a fiber optic strand. Any problems with the connectors, such as poor installation or uncleanness, can greatly reduce the light power transmitted and received. Since such problems may render the fiber optic system inoperative, understanding the installation of fiber optic connectors come to be a key element in building a successful fiber optic network.

From this tutorial, you can learn how to install fiber optic connectors properly. There are three common methods for installing fiber optic connectors, and any of them can be used to achieve high-quality, low-loss connector sets. The methods are Gluing and Polishing, Cleaving and Crimping, and Fusion Splicing Pigtails.

Gluing and Polishing

This is the most common method of connector installation. It is also the slowest and requires the most training and care by the technician to achieve consistently good connectors.

Steps: Strip the buffer coating and the 900-micron plastic jacket from the fiber end. Glue the epoxy into the body of the connector so that a small amount flows out of the ferrule end. Insert the fiber into the connector body, and place this assembly into an oven, which heats the connector, setting the epoxy glue. Remove the connector in the oven for cooling after 15 min. Scratch the excess fiber sticking out of the ferrule gently once the connector is cool enough to handle, using a jewel-tipped tool called a scribe. Polish the fiber gently after scribing and the fiber stub is removed with fingers, using two or three steps of successively finer polishing papers, a polishing puck, and a flat surface.

This method of connector installation requires AC power for the oven and a flat surface on which to polish. It is messy and time consuming. There are many steps towards completion, and any mistake will require the technician to start over at the beginning. An advantage is that the connectors are the least expensive, although the need for other consumables, such as glue, syringes, and polishing paper reduces the cost savings.

Cleaving and Crimping

This method is gaining in popularity, particularly among security technicians, where small numbers of connectors are usually installed. The connectors have a pre-polished fiber stub installed in the ferrule. They have been assembled at the factory, and have a quality of polish superior to any that can be performed in the field.

Steps: Strip the jacket and buffer coating from the fiber. Cleave the fiber to within two degrees of 90 degrees (perpendicular) at a specific length, using a special tool called fiber optic cleaver. (The pre-installed fiber stub in the connector has been cleaved at the factory.) Insert the cleaved fiber end into the back of the connector until it contacts the fiber stub within. Hold the two cleaved fiber ends together with an internal mechanical clamp. Crimp the back of the connector to the fiber's jacket, using a crimping tool.

This method of connector installation is fast, and can be performed in just a few minutes per connector. Because there is no glue, there is no need for AC power, glue and syringes. With the fiber pre-polished at the factory, connectors can be installed while standing on a ladder and no flat surface is needed. These connectors are more expensive than the glue-and-polish type, although the time saved by using them will save the contractor much more than the cost of the connectors. The quality of the cleaving is very important, because a mediocre or poor cleaving will lead to a poor or inoperative connector. Each cleaving should be inspected with a side-view 100-power microscope before insertion into the connector body. There are a number of vendors that offer cleave-and-crimp connectors, and they also supply complete tool kits for connector installation. Contractors should verify that the connection kit includes a side-view scope (some vendors do not include this critical item in their standard tool kits).

Fusion Splicing Pigtails

Fusion splicing pigtails is the fastest method of connector installation, and yields the highest-quality connectors. Fiber optic jumpers with the appropriate type of connectors installed, ST or SC, are purchased from a fiber optic supplier (e.g. Fiber-Mart). Because these connectors have been machine-polished, they have very high quality and low loss.

Steps: Cut the jumper cable in the center to produce two short fiber cables with connectors attached which are called fiber optic pigtails. Strip the fiber to be connected and the pigtail. Cleave the fibers with a fiber optic cleaver or fusion splicer. Splice the fibers together with the fusion splicer which is a fiber-specific device that can precisely align the cleaved fiber ends, passes an electrical arc of specific time duration across the fiber ends, and pushes them together.

This entire operation can be performed in minutes, and produces the highest quality connector installation. However, the high cost (several thousand dollars) of a new fusion splicer usually precludes most security installation firms from using this method. Fusion splicers may be rented for a few days, and there is a large quantity of fusion splicers available on the secondary market, at greatly reduced costs. If performing single-mode installations, particularly for telecommunications or cable television systems, this method of connector installation is usually required.

Summary

Fiber optics is an exact discipline, and requires complete knowledge and training for the technician to properly and safely perform connector installation. Many labor-hours have been wasted by unknowledgeable technicians not understanding the correct tools, methods, and hand skills needed for fiber optic work. When choosing an installation method, the company should consider costs for tools, time required to perform connections, and the level of technician training necessary. Well-trained technicians can install connectors with consistency and a high yield of good-quality connectors.