A variety of optical fiber connectors are available. Typical connectors are rated for 500-1000 mating cycles. The main differences among types of connectors are dimensions and methods of mechanical coupling. Generally, organizations will standardize on one kind of connector, depending on what equipment they commonly use, or per type of fiber (one for multimode, one for single-mode). In datacom and telecom applications nowadays small form factor connectors (e.g., LC) and multi-fiber connectors (e.g., MTP) are replacing the traditional connectors (e.g., SC), mainly to pack more connectors on the overcrowded faceplate, and thus reducing the footprint of the systems.
According to Telcordia GR-326, Generic Requirements for Single-Mode Optical Connectors and Jumper Assemblies, optical fiber connectors are used to join optical fibers where a connect/disconnect capability is required. The basic connector unit is a connector assembly. A connector assembly consists of an adapter and two connector plugs. Due to the sophisticated polishing and tuning procedures that may be incorporated into optical connector manufacturing, connectors are generally assembled onto optical fiber in a supplier’s manufacturing facility. However, the assembly and polishing operations involved can be performed in the field, for example, to make cross-connect jumpers to size.
Optical fiber connectors are used in telephone company central offices, at installations on customer premises, and in outside plant applications. Their uses include:Making the connection between equipment and the telephone plant in the central office,Connecting fibers to remote and outside plant electronics such as Optical Network Units (ONUs) and Digital Loop Carrier (DLC) systems,Optical cross connects in the central office,Patching panels in the outside plant to provide architectural flexibility and to interconnect fibers belonging to different service providers,Connecting couplers, splitters, and Wavelength Division Multiplexers (WDMs) to optical fibers,Connecting optical test equipment to fibers for testing and maintenance.
Outside plant applications may involve locating connectors underground in subsurface enclosures that may be subject to flooding, on outdoor walls, or on utility poles. The closures that enclose them may be hermetic, or may be “free-breathing.” Hermetic closures will subject the connectors within to temperature swings but not to humidity variations unless they are breached. Free-breathing closures will subject them to temperature and humidity swings, and possibly to condensation and biological action from airborne bacteria, insects, etc. Connectors in the underground plant may be subjected to groundwater immersion if the closures containing them are breached or improperly assembled.
Depending on user requirements, housings for outside plant applications may be tested by the manufacturer under various environmental simulations, which could include physical shock and vibration, water spray, water immersion, dust, etc. to ensure the integrity of optical fiber connections and housing seals.