Fiber optic connectors have traditionally been the biggest concern in using fiber optic systems. While connectors were once unwiedy and difficult to use, connector manufacturers have standardized and simplified connectors greatly. This increases the user use convenient increase in the use of optical fiber systems; It is also emphasising taken proper care of and deal with the optical connector. This article covers connector basics including the parts of a fiber optic connector, installing fiber optic connectors, and the cleaning and handling of installed connectors. For information on connector loss, see Connector Loss Test Measurement. Optical fiber to fiber optic interconnection can be made by a joint, a permanent connection, or a connector, and is different from the plug in it can be to disconnect and reconnect. Fiber optic connector types are as various as the applications for which they were developed. Different connector types have different characteristics, different advantages and disadvantages, and different performance parameters. But all connectors have the same four basic components.
The Ferrule: The fiber is installed in a long, thin cylinder, the ferrule, which act as a fiber alignment mechanism. The ferrule is bored through the center at a diameter that is slightly larger than the diameter of the fiber cladding. The end of the fiber is located at the end of the ferrule. Ferrules are typically made of metal or ceramic, but they may also be constructed of plastic.
The Connector Body: Also known as the connector housing, the body holds the ferrule. It is usually constructed of metal or plastic and includes one or more assembled pieces which hold the fiber in place. The details of these connector body assemblies vary among connectors, but the welding and/or crimping is commonly used to attach strength members and cable jackets to the connector body. The ferrule extends past the connector body to slip into the couping device.
The Cable: The cable is attached to the connector body. It acts as the point of entry for the fiber. Often, a strain relief boot is added over the junctioni between the cable and the connector body, providing extra stength to the junction.
The Coupling Device: Most fiber optic connectors do not use the male-female configuration common to electronic connectors. Instead, a coupling device such as an alignment sleeve is used to mate the connectors. Similar devices may be installed in fiber optic transmitters and receivers to allow these devices to be mated via a connector. These devices are also known as feed-through bulkhead adapters.
Cleaving Cleaving involves cutting the fiber end flush with the end of the ferrule. Cleaving, also called the scrible-and-break method of fiber end face preparation, takes some skill to achieve optimum results. Properly handled, the cleave produces a perpendicular, mirror-like finish. Incorrect cracks will cause the lips and the comb as shown in Figure 2. While cleaving may be done by hand, a cleaver tool, available from such manufacturers as Fujikura and FiberStore, allows for a more consistent finish and reduces the overall skill required. The steps listed below outline one procedure for producing good, consistent cleaves such as the one shown in Figure 3. 1. Place the blade of the cleaver tool at the tip of the ferrule. 2. Gently score the fiber across the cladding region in one direction. If the scoring is not done lightly, the fiber may break, making it necessary to reterminate the fiber. 3. Pull the excess, cleaved fiber up and away from the ferrule. 4. Carefully dress the nub of the fiber with a piece of 12-micron alumina-oxide paper. 5. Do the final polishing.
The use of index-matching gel, a gelatinous substance that has a refractive index close to that of the optical fiber, is a point of contention between connector manufacturers. Glycerin, available in any drug store, is a low-cost, effective index-matching gel. Using glycerin will reduce connector loss and back reflection, often dramatically. However, the index-matching gel may collect dust or abrasives that can damage the fiber end faces. It may also leak out over time, causing backreflections to increase.
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