Fiber optic connectors terminate both ends of an optical fiber. A variety of optical connectors is available. The differences between the types of connectors are size as well as the methods of coupling. There is four type of fiber optic connector in use:-
The ST connector was one of the first connector types broadly implement in fiber optic networking applications. Originally developed by AT&T, it stands for Straight Tip connector. ST connections use a 2.5mm ferrule with a round plastic or metal body. The connector stays in place with a “twist-on/twist-off” bayonet-style mechanism. Although extremely popular for many years, the ST connector is slowly replaced by smaller, denser connections in many installations.
SC connectors also use around 2.5mm ferrule to hold a single fiber. They use a push-on/pull-off mating mechanism which is usually easy to use than the twist-style ST connector when in tight spaces. The connector body of an SC connector is square-shaped, and two SC connectors are usually held together with a plastic clip (this is referred to as a duplex connection). The SC connector was developed in Japan by NTT (the Japanese telecommunications company) and believed to be an abbreviation for Subscriber Connector or possibly Standard Connector.
One popular Small Form Factor (SFF) connector is the LC type. This interface was developed by Lucent Technologies (hence, Lucent Connector). It uses a retaining tab mechanism; similar to a phone or RJ-45 connector, and the connector body resembles the square type shape of SC connector. LC connectors normally held together in a duplex configuration with a plastic clip. The ferrule of an LC connector is 1.25mm.
Full Duplex patch cords
As we know that light can move in one direction over optical fiber. Two fiber required for full-duplex communication. So, fiber-optic patch cables bundle together two optical fiber cables and terminate them with a pair of standard single fiber connectors. Some fiber connectors also accept both the transmitting and receiving fibers in a single connector known as a duplex connector as shown in below figure Duplex Multimode LC Connector. Fiber patch cords also required for interconnecting communications devices. The figure shows a variety of common patch cords. The use of color distinguishes between single-mode and multimode patch cords. A yellow jacket is for single-mode fiber cables and orange (or aqua) for multimode fiber cables.
Note: A small plastic cap protect the fiber optic cable when not in use.