Fibre optic connector guide

6 December 2017

Simply put, a fibre optic connector is hardware that terminates the end of a fibre optic cable to provide attachment to a transmitter, receiver or other cable and allow for re-mateable connections. Whether you are installing a brand new fibre optic network, adding a connection or repairing a legacy system, using this fibre optic connector guide will help you identify the connector you are looking at or what type of connector you need.


What are the 4 most common fibre optic connectors?

Although there are more than 100 types of fibre optic connectors in the marketplace, the 4 most common ones are ST, SC, FC and LC.

ST Connector
ST Connector

ST connectors were one of the first connector types widely implemented in fibre optic networking applications. Originally developed by AT&T, ST stands for ‘Straight Tip’ connector.

The ST connector utilises a 2.5mm ferrule with a round plastic or metal body. The connector stays in place with the help of a “twist-on/twist-off” bayonet-style lock mechanism.


SC Connector

SC Connector

The SC connector was developed in Japan by NTT (the Japanese telecommunications company), and is believed to stand for ‘Subscriber Connector’ or ‘Standard Connector’.

SC connectors use a round 2.5mm ferrule and come with a locking tab that enables push on / pull off mating mechanism to offer quick insertion and removal. The SC connector can be utilised with single-mode and multi-mode fibre optic cables.

The connector body of an SC connector is square shaped. Two SC connectors are commonly bound together with a plastic clip, creating a duplex connection.


FC Connector

FC Connector

FC is an acronym for ‘ferrule connector” or ‘fibre channel’.

The connectors have a threaded body and a position locatable notch to achieve exact locating of the SMF in relation to the receiver and the optical source. Once the connector is installed, its position is maintained with total precision.

The FC is designed for durable connections, and can be used in high-vibration environments.


LC Connector

LC Connector

Developed by Lucent Technologies, the LC connector otherwise known as a ‘Lucent Connector’ measures about half the size of an SC connector.

Available in simplex or duplex versions, LC connectors can be used with both single-mode and multi-mode cables.

The LC connector uses a 1.25mm ferrule with a retaining tab mechanism.




There are 3 major components of a fibre connector:

Ferrule — this is a thin structure (often cylindrical), usually made from ceramic, metal, or high-quality plastic, that forms a tight grip on the fibre.

Connector body — this is a plastic or metal structure that holds the ferrule and attaches to the jacket and strengthens members of the fibre cable itself.

Coupling mechanism — this is a part of the connector body that holds the connector in place when it gets attached to another device. It may be a latch clip, a bayonet-style nut, or similar device.


Why is it important to choose a good quality fibre optic connector?

Traditionally, not much thought is given to connector selection beyond cost, availability or what’s been used before. However the quality of the optical fibre connector can have a dramatic impact on deployment speeds and costs.

Fibre optic cables carry information between two places using entirely optical (light-based) technology. For the light pulses to transmit effectively, fibre optic connectors must mechanically couple and align the cores of the fibres perfectly. This sort of connection has to be highly precise in order to facilitate high speed fibre optic networking.

Good quality connectors, like those supplied by TXO Optics, lose very little light due to reflection or misalignment of the fibres.