Fibre optic connectors - types and overview

The worldwide data volume is growing rapidly. Driven by increasing digitalisation, the demands placed on data centres are constantly rising. Huge amounts of data must be transferred quickly, securely and reliably. As a result, the demands on data centre components such as fibre optic connectors are also growing, since they have a decisive influence on signal transmission.
High-quality connectors ensure highest data transmission rates and continuous availability. For this reason, the insertion loss (dB) and return loss (dB) values must be influenced by the connection as little as possible. Other requirements for fibre optic connectors are: easy handling, mechanical stability in continuous operation, and low space requirements.
This makes it all the more important to select, use and maintain fibre optic connectors correctly.

Optical fibre cables can be equipped with a variety of connectors. The list below provides you with an overview of the commonly used connectors.

LC connector

The LC is a small-form-factor connector system for optical fibre cabling in compliance with the standard DIN EN 61754-20. The new generation of LC COMPACT connectors has a compact end housing which perfectly protects the fibres and permits reliable strain relief for the various cable types. Versions: multimode and singlemode, normal and oblique cut. LC connector (PC and APC). 
Ferrule: Zirconia-ceramic, Ø 1.25 mm

MPO/MTP^® connector

The abbreviation MPO stands for “Multi-fibre Push-on Connector”. It is a push-on connector for multi-fibre cables consisting generally of 6, 8, 12 or 24 fibres. The MPO push-on connector is often referred to as an MTP^® connector. MTP^® is a registered trademark of US-Conec Ltd.

SC connector

The SC is an optical fibre push-on connector in compliance with DIN standard IEC 61754-15 for applications in the telecommunications sector, data centres, LAN cabling and for connecting active components. Versions: multimode and singlemode, normal and oblique cut. SC connector (PC and APC). The SC/APC push-on connector has an oblique, polished ferrule front face (8° or 9°). The light that is reflected here is no longer capable of propagation. Reflections are reduced to a minimum. This makes it possible to achieve a higher return loss. APC connectors are preferentially used for singlemode cables.
Ferrule: Zirconia-ceramic, Ø 2.5 mm

E-2000^® connector

The E-2000^® connector is an optical fibre push-on connector in compliance with international standard IEC 61754-15. It possesses a push-pull locking mechanism and a self-closing dust protection flap. Design: multimode and singlemode, normal and oblique cut. E-2000^® connector, PC and APC.
Ferrule: Zirconia-ceramic, Ø 2.5 mm

Expanded beam connectors

Due to the optical expansion of the beam, expanded beam connectors are less sensitive to contamination than conventional fibre-optic push-on connectors. In combination with high-quality cables, they are primarily used in harsh environments.

Expanded Beam Optical (EBO) Latch Connector 3M^™
The expanded beam ferrule of the Expanded Beam Optical (EBO) Latch Connector 3M^™ is currently available in the 12-fibre multimode and singlemode versions and will be available in a 16-fibre multimode and singlemode variant in the future. Depending on the type and size of the connector housing, one or more ferrules can be accommodated in a single connector.

Connector technology for optical fibres (OF):

APC (Angled Polished Contact)
Some fibre optic connectors are available not only as a PC (Physical Contact) but also as an APC variant (Angled Physical Contact). 
Grinding the fibre endface at an angle - usually 8°- means that reflected light is no longer propagated. Reflections are reduced to a minimum.

Duplex vs Simplex
Duplex: Transmission mode in which data can be simultaneously transmitted in both directions. Duplex transmission is therefore also referred to as two-way transmission (as per DIN).
Simplex: Transmission mode in which data can only be transmitted in one direction. There is no return path or return channel. Simplex transmission is therefore also referred to as one-way transmission (as per DIN).

Ferrule 
Connector pin (usually ceramic) responsible for ensuring the precise axial guidance of the fibre in the connector.

Multimode fibre (MMF)
Type of fibre in whose core multiple waves (modes) are able to propagate. The number of modes depends on the size of the fibre core. Typical dimensions are 50 / 125 µm and 62.5 / 125 µm. The classes OM1, OM2, OM3, OM4 and OM5 exist for multimode optical fibres.

Singlemode fibre (SMF)
Fibre in whose core only one light wave (mode) is capable of propagation. Usual size: 9 / 125 μm.

The performance capabilities of fibre optic cabling are crucially dependent on the cleanliness of the fibre ends. Even small particles of dirt or other contaminants such as grease or dust can significantly impair the transmission properties of a fibre optic connection. Depending on the structure of the fibre optic connector, special equipment and the corresponding expertise may be needed for cleaning.
See here for more information and an overview of tools for cleaning loose and installed optical fibre connectors.

Cable assembly refers to the manufacture of connection-ready cables, cable bundles and entire wiring harnesses by equipping them with connectors, contacts or fibre end sleeves.
Rosenberger OSI is one of Europe’s largest producers of assembled MTP^® cables. In total, we assemble approximately 4 million push-on connectors every year in our production and logistics centres in Taksony (Hungary) and Apodaca (Mexico). Optical fibre push-on connectors such as LC, SC, MDC, MTP^®/MPO, MU, MXC^®, E-2000^®, FC or ST connectors or expanded beam connectors may be used for cable assembly.

Thanks to our extensive production and delivery capabilities and our state-of-the-art manufacturing methods, we offer very short delivery times irrespective of batch size.

• 4,700m² production area
• 3,400m² storage area

Ultimately, our outstanding delivery capabilities and high-end products ensure trouble-free installation and stable long-term performance. We only use our own push-on connectors or connectors from renowned high-quality manufacturers that are guaranteed to be qualified in accordance with applicable standards and reliably conform to international specifications.

We perform cable assembly in accordance with precise standards. And we even exceed standards: e.g. the insertion loss (IL) of our PURE quality for 50 µm multimode is lower than that of the most exacting performance class specified in standard IEC 61755-5 Ed. 1.0 CD Grade CM.

In our online shop, you will find a wide range of products for optical fibre cabling, such as trunks, patchcords, pigtails or 19-inch panels with common optical fibre connector types such as LC, SC, MTP^®/MPO, MU, MXC^®, E-2000^®, FC or ST. Whether simplex, duplex or multifiber, singlemode or multimode – this is where you will find the right solutions for your applications. Many items are available ex-stock. Fast delivery: 1-2 working days. No minimum order amount. Carriage-free as of an order value of €100.

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