Optical fiber connector

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Duplex LC connector

Duplex MT-RJ connector

SC connectors

ST connector

TOSLINK connector

An optical fiber connector terminates the end of an optical fiber, and enables quicker connection and disconnection than splicing. The connectors mechanically couple and align the cores of fibers so that light can pass. A variety of optical fiber connectors are available. 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 singlemode).

1 Types
- 1.1 Mnemonics
2 Analysis
3 References
4 External links

[edit] Types

Common fiber connectors
Short name	Long form	Coupling type	Typical applications
ESCON	Enterprise Systems Connection	Duplex Snap	Wall outlets
FC	Ferrule Connector	Screw	Datacom, telecom, Single mode lasers (becoming less common)
FDDI	Fiber Distributed Data Interface	Duplex Snap	Wall outlets
LC	Lucent Connector / Local Connector	Snap	High-density connections, SFP transceivers
MT	Mechanical Transfer	12-plex Snap	Preterminated cable assemblies
MT-RJ	Mechanical Transfer Registered Jack	Duplex Snap	Duplex multimode connections
MU		Snap	Miniature connector common in Japan
SC	Subscriber Connector / Standard Connector / Siemon Connector	Snap	Datacom
ST / BFOC	Straight Tip / Bayonet Fiber Optic Connector	Bayonet	Multimode networks
TOSLINK	Toshiba Link	Snap	Digital audio

Less common fiber connectors
Short name	Long form	Coupling type	Typical applications
Biconic		Screw	Obsolete
D4		Screw	Telecomm, obsolete
E-2000		Snap
F-3000		Snap
MIC	Media Interface Connector
MPO	Multi-Fibre Push On	Snap
MTP		Snap
Opti-Jack		Duplex Snap
SMA	Sub Miniature A	Screw	Industrial (Lasers)
SMC	Sub Miniature C	Snap

If the fiber-end is angled to reduce back reflections this is usually described by adding "APC" (Angled Physical Contact) to the name.

[edit] Mnemonics

LC connectors are sometimes called "Little Connectors".
MT-RJ connectors look like a miniature 8P8C connector — commonly (but erroneously) referred to as RJ-45.
ST connectors have a mnemonic of "Stab and Twist", referring to how it is inserted (the cable is pushed into the receiver, and the outer barrel is twisted to lock it into place). Also they are known as "Square Top" due to the flat end face.
SC connectors have a mnemonic of "Square Connector", and some people believe that to be the correct name. This refers to the fact the connectors themselves are square. Another term often used for SC connectors is "Stick and Click".
FCA are referred to as "Fiber Connector Angled".

[edit] Analysis

FC connectors' floating ferrule provides good mechanical isolation. FC connectors need to be mated more carefully than the push-pull types due to the need to align the key, and due to the risk of scratching the fiber endface while inserting the ferrule into the jack. FC connectors have been replaced in many applications by SC and LC connectors.^[1]
There are two common types of FC connectors, FCA and FCU. FCAs, unlike their FCU counterparts, have an angled end face which reduces the amount of light reflected back to the transmitter by bending the wave at the connectors. Similar to shining a flashlight directly at a mirror as opposed to angling it down. FCAs are distinguished with a green boot for strain relief. FCUs look identical but have a flat top.
SC connectors offer excellent packing density, and their push-pull design reduces the chance of fiber endface contact damage during connection.
LC connectors are replacing SC connectors in corporate networking environments due to their smaller size; they are often found on small form-factor pluggable transceivers.
ST connectors have a key which prevents rotation of the ceramic ferrule, and a bayonet lock similar to a BNC shell.
In general the insertion loss should not exceed 0.75 dB and the return loss should be higher than 20 dB. Typical insertion repeatability, the difference in insertion loss between one plugging and another, is 0.2 dB.
On all connectors, cleaning the ceramic ferrule before each connection helps prevent scratches and extends the connector life substantially.