Fibre Connector Types for Fibre Optic Cables: A Complete Guide
A Fibre Connector offers a mechanical means to terminate optical cables. In other words, they make the meters per second devices. The connector’s main role is to hold the end of the fibre precisely in place. By doing this it ensures the maximum light transfer happens.
Fibre optic connectors are referred to as male connectors. This is due to the protruding ferrule that is used to hold and align the fibres.
Ceramic ferrules were introduced in the mid-80s. They were designed to make alignment even more precise. You could now hold the ferrule as it was robust. The ferrule design was a 2.5mm ceramic cylinder which allowed for mix and matching between connectors with that same ferrule size. The most common examples of these are ST, SC, and FC connectors.
Most importantly, this ceramic ferrule design allowed us to connect directly to active devices like LEDs, VCSELs, and detectors.
A curved ferrule end face for physical contact between connectors reduced losses. Most importantly providing loss levels below 0.3 decibels for both Multimode and Singlemode varieties. For more information on polish facts visit this blog!
What does colour have to do with connectors?
Coloured boots used from very early on helped differentiate between multimode fibre and Singlemode fibre. Beige for multimode. Blue for Singlemode connectors and Green for Angled Physical contact connectors.
We also use different colour jackets in Fibre Optic Patch Cables to distinguish the various cable types available.
- Orange cable for Multimode OM1
- Aqua cable for Multimode OM3
- Erika Violet for Multimode OM4
- Lime Green for Multimode OM5
- Yellow for Singlemode.
Most Common Fibre Connector
Let’s examine the most common fibre optic connectors.
ST Fibre Connector
ST, Straight tip, or Standard Turn Connector (an AT&T Trademark). This connector meets IEC 61754-2 standards. It is a fibre optic connector that uses a half-twist bayonet type of lock. It has a 2.5mm keyed cylindrical ceramic ferrule. The ST connector is spring-loaded for easy mating.
SC Fibre Connector
SC, Standard Connector, Square Connector, Standard Click, or also referred to as a Subscriber Connector. This connector meets IEC 61754-4 standards. It is a snap-in fibre optic connector that uses a push-pull latching mechanism. Similar to common audio and video cables. It has a 2.5mm ceramic ferrule and can be mixed with any other 2.5mm ferrule using a hybrid adaptor.
FC Fibre Connector
FC, Field assembly connector, Fibre Channel or Ferrule Connector. This connector meets IEC 61754-13 standards. It was the most popular Singlemode connector for many years. The FC connector has a threaded body which is particularly good for high-vibration locations. You can mate it to any 2.5mm ferrule. It screws on firmly and is still provided on test and measurement equipment. SCs and LCs are more popular.
LC Fibre Connector
LC, Lucent Connector, Little connector, or Local connector, This connector meets IEC 61754-20 standards. It is a small form factor connector that uses a 1.25mm ferrule. This is half the size of an SC connector. The small size and latch feature make it highly suited for high-density connections and SFP transceiver modules.
MPO Connectors/MTP Connectors
MPO stands for Multi Fibre Push-on and MTP stands for Multi Fibre Termination Push-on. US Conec developed and trademarked the MTP version of the MPO connector.
MPO is a specific interface type that is defined by IEC 61754-7. This connector is a multiple fibre core connector.
These connectors are interchangeable with some of the main differences being that;
- MTP has a removable housing allowing for quick gender change and re-polishing if required.
- The MTP guide pinhole can handle approximately 500 matings before deterioration compared to 50 matings for an MPO connector.
- An MTP has a floating ferrule allowing two mated ferrules to maintain physical contact while under an applied load.
This type of connector combines lots of fibres in one connector. Which means a reduction in the time it takes to connect fibres. Whilst also saving a lot of space in the process. 8, 12 and 24 fibre MPO/MTP connectors are used in today’s communication and data-centre industry.
MTP/MPO connectors are a pin and socket style connector which requires a male side and a female side.
You can identify a male connector by the two alignment pins protruding from the end of the ferrule. The MPO female connectors have holes in the ferrule to accept the alignment pins from the male connector. Male connectors are used at endpoints. Such as in a fibre patch panel or fibre cassette for re-distribution.
Polarity
Not only do we need to know if the MPO/MTP connector is male or female we use the term polarity with MPO/MTP connectors as well. The positioning of the fibres inside the cable determines what the polarity will be.
There are 3 polarities to consider when designing a network;
1. Type-A MPO Trunk Cable:
Type-A cable has a key up MPO connector on one end and a key down MPO connector on the opposite end. This makes the fibres at each end of the cable have the same fibre position. The following picture shows the fibre sequence of a 12 fibre Type-A cable.
2. Type-B MPO Trunk Cable:
Type-B cable (reversed cable) uses key up connector on both ends of the cable. This type of array mating results in an inversion. Fibre positions are reversed at each end. The following picture shows the fibre sequences of a 12 fibre Type-B cable.
3. Type-C MPO Trunk Cable:
Type-C cable (pairs flipped cable) looks like a Type-A cable with one key up connector and one key down connector on each side. Fibres at one end are flipped at the other end. The following picture shows the fibre sequence of 12 fibre Type-C cable.
Why do we have all these different options?
There is no debate about which of these options is the better one. The reason we have all these different choices is that manufacturers have diverse approaches. Providing many different solutions. Thus, it is merely a matter of which of these options will work the best in the solution chosen.
You fix the Polarity when manufactured. You can then no longer change it. All components within the network will have a component polarity; patch cords (A-B or A-A), MPO cassettes (A, B or C), and MPO trunks (A, B or C). As a result of this, for the link to work correctly all these component polarities must be correct!
Types of an Optical Fibre Connector Explained
There are several types of optical fibre connectors used in data and communication networks. Each has different features, shapes, and applications.
Common Connector Types
-
LC Connector
Small and reliable. Often used in modern switches, SFP modules, and patch panels. -
SC Connector
Snap-in style. Common in datacentres and older enterprise networks. -
ST Connector
Twist-lock design. Mostly found in legacy systems and some test environments. -
MPO/MTP Connector
High-density, multi-fibre connectors. Perfect for large-scale, high-speed connections. -
FC Connector
Screw-in style. Mostly used in lab environments or precise testing scenarios.
Fibre Connector Characteristics
Each connector has unique performance features:
-
Insertion Loss: Measures signal loss at the connector point. Lower is better.
-
Return Loss: Measures reflected signal. Higher return loss means better quality.
-
Polish Types: UPC (flat) and APC (angled). APC connectors reduce reflection and are better for long-distance runs.
What Are OFC Fibre Connector Types?
OFC stands for Optical Fibre Cable. The term OFC connector types refers to the different types of connectors used with fibre optic cables.
Connector Types Depend On:
-
Fibre Mode
-
Single-mode uses yellow jackets and works over long distances.
-
Multi-mode uses orange or aqua jackets for shorter, high-speed links.
-
-
Connector Style
Common styles include LC, SC, ST, FC, and MPO. Each fits different devices and patch panels. -
Application Type
Use LC or SC for patching. Use MTP/MPO for high-density fibre trunks. ST and FC are better for labs or legacy setups.
Choosing the right fibre cable connector type ensures proper fit, low signal loss, and strong connections.
FAQs About Fibre Connectors
What are the most common fibre connector types?
The two most common fibre optic connector types are LC and SC.
-
LC connectors are compact and use a latch mechanism. They’re widely used in modern switches, SFP modules, and patch panels.
-
SC connectors are larger with a push-pull locking mechanism. You’ll often find them in datacentres and older enterprise systems.
Other connector types include ST (twist-lock), FC (screw-on), and MPO/MTP (high-density multi-fibre).
To see where these connectors are used in real-world networks, visit our guide on fusion splicing and installation best practices.
What is the difference between an SC and a LC fibre connector?
LC connectors are smaller and use a push-latch. They’re ideal for tight spaces and modern high-density equipment.
SC connectors are larger and snap into place with a locking tab. They’re easier to handle but take up more space.
Both perform well — the choice depends on port compatibility and available space.
For a full overview of different fibre cable types, read our article: Cat5e vs Cat6 vs Cat6a: Which Is Best for You?
Can I mix different fibre connector types on the same network?
Yes, but only by using adapter cables or hybrid patch leads.
For example, an LC-to-SC patch lead can connect two different port types.
Make sure to match:
-
Connector type
-
Polish type (UPC or APC)
-
Fibre mode (single-mode or multi-mode)
Mixing is possible but requires care to avoid performance loss.
To learn more about matching connectors to your cable setup, visit our RJ45 pinout and termination guide.
Is a fibre connector interchangeable?
No. Connectors must match the port on your device or panel.
You can’t connect LC to SC directly without an adapter.
Always check the connector type, polish, and fibre mode before connecting.
What is the difference between UPC and an APC fibre connector?
UPC (Ultra Physical Contact) connectors have a flat polish. They offer low insertion loss and are common in general networking.
APC (Angled Physical Contact) connectors have an angled polish. They reduce back reflection and are better for long-distance or video applications.
Important: UPC and APC connectors are not compatible. Never connect one to the other.
Want to learn where APC connectors are used in new builds? See our breakdown of NBN installation setups in Australian homes.
How do I choose the right fibre connector for my project?
Start by checking your device ports — LC and SC are most common.
Match the polish type to your application: use APC for long-distance or reflection-sensitive setups.
Choose single-mode for long runs and multi-mode for short, high-speed links.
Use LC or SC for standard patching, and MTP/MPO for high-density environments.
If unsure, check the device label or product manual for connector requirements.
Need help comparing cable specs? Read: Cat5e vs Cat6 vs Cat6a
Need help terminating ends? Follow our RJ45 connector setup guide
Conclusion
In conclusion, You need Fibre Optic Connectors to connect to other fibres and active devices. There are two main Ferrule sizes; one with an OD size φ2.5mm and the other with a Ferrule OD size of φ1.25 mm. Whilst there are many different types of fibre connectors, they still share similar design characteristics. Some are legacy connectors and still required, others provide the latest technology with extremely low losses and back reflections!