The Ultimate Guide to Connector Types

The purpose of a connector is to allow light to travel through a cable to create a secure connection without interruption. Every time you connect to the internet, make a phone call or stream your favourite show, a fibre optic connectors link enables that connection. 

As you may know, there are many different connectors available, so being able to choose the right type will ensure ideal network performance. 

What do connectors do?

Connectors maintain physical contact between the fibres inside each of the ferrules, allowing light to travel from one fibre to another. This is achieved in part through a precise alignment of the fibres, ensuring that the cores of the two fibres are aligned, to maintain the signal quality and minimise signal loss.

A connector’s ability to securely hold the fibres in place prevents damage or disconnection during installation, handling, or from environmental factors which ensures the connection remains reliable and stable, even in harsh environments.

Optical fibre connectors are available in various formats and sizes, with the most common single fibre connectors being SC, LC, ST, and FC. For multi-fibre connections, MPO/MTP is the most common. Each type of connector has specific characteristics and advantages such as:

•    The number of fibres it can support
•    The kind of fibre it can accommodate
•    It’s level of durability

They are also designed to be compatible with a wide range of devices and systems, making them a versatile tool for anyone working with optical fibres.

The anatomy of a fibre optic connector

Ferrule
The purpose of a ferrule is to align and protect the fibre(s) within the connector. The hole through the ferrule must be big enough to fit the clad fibre and tight enough to hold the fibre in a fixed position. Ferrules can have different angled end faces depending on the application however, the end face needs to be smooth and clean to reduce signal loss. 

Connector body
The connector body is the part of the connector that houses the ferrule and provides additional alignment for the optical fibre, essential for minimising signal loss and maintaining network integrity. The body is attached to the cable structure and is the largest portion of the connector.

Cable
The cable contains various types of fibres defined by their function and application. Cables hold single-mode or multi-mode fibres and can differ depending on application, distance, and data requirements. The cable is attached to the connector body and acts as a point of entry for the fibre.

Coupling mechanisms
Optical connectors use various coupling mechanisms to ensure secure connections. The choice of mechanism depends on application, environmental conditions, ease of use, and the need for high port density. 
 

Types of fibre optical connectors

•  SC connectors are a type of push-pull connector which are mostly popular for use in telecoms networks. SC connectors are built around a cylindrical ferrule that holds the fibre, which them mates with an interconnection adapter or coupling receptacle. It has a square cross-section which allows for high packing density on patch panels. It can easily be packaged in a duplex or a quad version.

• ST Connectors use a bayonet-style twist lock mechanism and were used widely in local area networks but are now more commonly used in industrial applications. 

• LC connectors are known for their small size, resulting in high port density. They are a RJ-based (Radio Jack) latching connectors, which makes them ideal for high-density applications in data centres and telecommunication applications. LC connectors have a snag-free latch, which creates the “snap” sound upon engaging. These connectors are designed for low insertion loss and are commonly used in a duplex configuration, meaning they can support two fibres for bidirectional communication.

• FC connectors are screw-on type connectors which are often used in industrial, medical, and research applications. z optical loss is like ST and SC connections and can resist pulling forces.

•  MPO connectors are a type of multi-fibre connector providing high-density connectivity, allowing for multiple fibre strands to be connected in a single device. This design enables higher bandwidth and increased data transfer rates, making it a popular choice for data centres and other high-bandwidth applications. MTP connectors are a type of MPO connector that offers an additional feature – an excess floating ferrule mechanism. This mechanism ensures the connector remains in contact with a fixed ferrule (e.g. in a transceiver) even when subjected to mechanical stress or tension, such as when cables are being pulled, adjacent working or when the connector is being mated.

• DDK connectors are specialised heavy-duty and highly reliable connectors for use in a range of industries and differing applications. DDK connectors are known for their robust construction and ability to withstand extreme environmental conditions.

Choosing the right connector 

Finding the right connector comes down to understanding the requirements of the application. All connectors have pros and cons so depending on your specific application needs, some connectors will be more suitable than others. 
Connectors tend to be industry-specific, such as oil and gas, military, railway or telecommunications. Here are some factors to consider: 

1. Fibre type: Consider the type of fibre you are using – single-mode, multi-mode, large-core, multi-core, etc
2. Fibre size: Ensure the ferrule is compatible with the size of your fibre.
3. Operating temperature: It’s important that your connector can withstand it the temperature in which it will be working.
4. Environmental conditions: Consider the environmental conditions in which the connector will be used. Factors such as humidity, vibration, shock and extreme temperatures could all have an impact.
5. Loss budget: How much maximum insertion loss (dB) is acceptable?
6. Back reflection: How much back reflection (dB) is acceptable?
7. Durability: In other words, whether the connector can withstand repeated connections and disconnections.
8. Ease of use: Because installing, maintaining, and repairing connectors takes time.

Conclusion: 

Choosing the right fibre optic connector is not just about selecting one at random. You need to know the specific requirements of your application before selecting a connector that meets those needs. By understanding the different parts of a fibre optic connector, the various types of connectors available, and the factors to consider when choosing the right one, you can ensure that your network will operate efficiently and effectively.

For further information on fibre optic connector types, contact us with your enquiries.