Installing Connectors

All of the common types of connectors are fairly simple to install, although you can expect a 10-percent loss until installers have a few days worth of experience. After that, figure on losses of 2 to 5 percent, depending on the cleanliness of the area in which the connections are made.
Before the installation of connectors onto a fiber cable, a breakout kit may have to be installed. This procedure will not be necessary on breakout cables having 2-mm buffered fibers, but will be required on 250-, 500-, and 900-micron tight-buffer cables. The breakout kit consists of a buffer tubing (usually 2 mm) over a 900-micron inner tubing. The bare fibers are inserted into these buffer tubes to provide handling protection and strength when mounted onto connectors.
Installing a fiber connector onto a pigtail or unbuffered fiber can be done in several ways. The three most common are epoxy glue with oven-cure, then polish; Hot Melt pre-glue, then polish; and cleave and crimp, no polish.
The epoxy-glue method is the oldest and is still widely used today. This process involves filling the connector with a mixed two-part epoxy, then insetting the prepared and cleaned fiber into the connector. After curing the epoxy in an oven for the specified period of time (usually 5 to 20 minutes) the fiber is scribed and cleaved nearly flush with the end of the connector. Finally, it's polished with a succession of finer and finer lapping papers (typically ranging from 3-micron grit down to 0.3- micron grit).
With the Hot Melt method (a trademark of 3M Co.), the connector come preloaded with glue and must be place into an oven to soften the glue. Clean, prepared fiber is then inserted into the connector, then left to cool. After cooling, fiber is scribed and polished in the same process as used in the epoxy method.
Cleave and crimp connectors do not require a polish procedure since these connectors already have a polished ferrule tip. Thus, installation simply involves inserting a properly cleaved fiber to butt against the connector's internal fiber "stub." The fiber connector is then crimped to hold the fiber in place. Each mounting method has advantages and disadvantages, varying from ease of installation to cost per connector to performance qualities.



Source:www.elec-toolbox.com/communications/classifications/fiber/fiber.htm