May292019

Fiber Optic Connectors

Fibre optic connectors terminate both ends of an optical fiber. A variety of fiber optic connectors are available. The differences between the types of connectors are the size and the coupling methods. There are four types of fiber optic connectors in use. The list of all kinds of fiber optic connectors is as follows: We should discuss the first four in detail.

Table of Contents

ST Connector (ST)
Standard Connector (SC)
Lucent Connector (LC)
Ferrule Core Connector (FC)
Bionic Connector
SMA Connector
E2000 Connector
Enterprise Systems Connection Connector (ESCON)
Plastic Fiber Optic Cable Connectors
MT Connector
Opti-Jack Connector
Fiber Distributed Data Interface Connector (FDDI)
LX-5 Connector
Volition Connector
MU Connector
MT-RJ Connector

ST Connectors

The ST connector was one of the first types broadly implemented in fiber optic networking applications and was the most popular connector for the multimode network. AT&T ST originally developed it as a straight-tip connector. ST connectors use a 2.5mm ferrule with a round plastic or metal body. They stay in place with a “twist-on/twist-off” bayonet-style mechanism.

Although extremely popular for many years, the ST connector has slowly been replaced with more miniature, denser connectors in many installations. The SC/FC/FDDI/ ESCON connectors have the same ferrule size—2.5 mm or about 0.1 inch—so they can be mixed and matched using hybrid mating adapters. ST connectors are spring-loaded, so it is necessary to make sure they are correctly seated. If you have a high loss, open the connector and reconnect it to see if it makes a difference.

SC Connector

Simple, rugged, and low-cost, SC connectors use a ceramic 2.5 mm ferrule to deliver accurate alignment of the SMF. They use a push-on/pull-off mating mechanism, which is usually easier than the twist-style ST connector when in tight spaces. The connector body of an SC connector is square-shaped.

Two SC connectors are usually held together with a plastic clip (a duplex connection). Japanese telecommunications company NTT originally developed SC, which is believed to be an abbreviation for Subscriber Connector or possibly Standard Connector.

LC connector

The Lucent Connector, sometimes called the Little Connector, is a popular Small Form Factor (SFF) connector. Lucent Technologies developed this interface. It uses a retaining tab mechanism, similar to a phone or RJ-45 connector, and the connector body resembles the square-type shape of an SC connector.

LC connectors are typically held together in a duplex configuration with a plastic clip. The ferrule of an LC connector is 1.25mm. There are 3 different types of LC connectors:

Single Mode LC APC
Single Mode LC UPC
Multi-Mode LC UPC

Ferrule Core Connector (FC)

FC Connectors_Fiber optic Connectors — Fiber Optic Connectors 8

The Ferrule Core Connector (FC) was the most popular single-mode connector for several years. It uses a 2.5 mm ferrule core, but some early connectors used ceramic inside stainless steel ferrules.

It screws on firmly, but you must make sure you have the key aligned; in the slot properly before tightening the FC connector is a pretty common choice, for example, in Video over Fiber Transmission Equipment.