A Lucent Connector (LC), as one SFF (small form factor) connector, possesses a 1.25 mm ferrule. The small footprint design gives these fiber optic connectors huge popularity in datacoms and makes them more ideal for high-density applications. Many tend to move to high-efficiency cabling with LC fiber connectors nowadays. LC fiber optic connector is considered the most commonly-used connector at present.
SC fiber connector was the first connector chosen for the TIA-568 standard and is a snap-in connector that latches with a simple push-pull motion. "SC" stands for "Square Connector" due to the "square-shaped" connector body. It adopts a 2.5mm ferrule, which is twice the size of the previous LC connector. SC fiber optic connector is ideally suited for datacoms and telecom applications including point to point and passive optical networking. Due to its excellent performance, fiber optic SC connector remains the second most common connector for polarization maintaining applications.
Unlike the previous two fiber optic conneceors, the MTP/MPO fiber connector is a multi-fiber connector and larger than other connectors, which combines fibers from 12 to 24 fibers in a single rectangular ferrule. It‘s often used in 40G and 100G high-bandwidth optical parallel connections. The MTP/MPO fiber connectors are complicated due to the key-up and key-down, male and female issues. You can refer to our white paper Understanding Polarity in MTP/MPO System to have a better understanding.
ST (Straight Tip) fiber optic connector was created and licensed by AT&T shortly after the arrival of the FC type. The ST optic connector holds the fiber with a ceramic, spring-loaded 2.5mm ferrule that stays in place with a half-twist bayonet mount. They are usually used in both long and short distance applications such as campuses and building multimode fiber applications, corporate network environments, as well as military applications.
"FC" refers to the Ferrule Connector. FC fiber optic connector was the first optical fiber connector to use a ceramic ferrule. Unlike the plastic-bodied SC and LC connector, it utilizes a round screw-type fitment made from nickel-plated or stainless steel. The FC fiber optic connector end face relies on an alignment key for correct insertion and is then tightened into the adaptor/jack using a threaded collet. Despite the additional complexity both in manufacturing and installation, the FC connectors still provide the choice in precision instruments such as OTDRs, as well as the choice for single mode fiber. It was initially intended for datacoms and telecoms applications but was used less since the introduction of the SC and LC fiber optic connectors. The usage of both ST and FC connectors have declined in recent years.
