Fiber Optic Connectors

Types of Fiber Optic Connectors

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Nowadays, a great variety of fiber termination connectors are available that allow fast connection and disconnection of the optical fibers. In this post we will describe the most used in the market:

SC Connectors (Subscriber Connector or Square Connector): Currently, its use in GPON and CATV networks has been generalized and we will analyze it later in more detail.

LC Connectors (Lucent Connector): Connector of smaller dimensions and used primarily in transceivers.

FC connectors (Ferule Connector): Metal connector with threaded connection system.

Connectors ST (Straight Tip) with metallic connector connection system bayonet turn.

Since in GPON systems the widely installed connectors are SC types, we will study their different types:  PC, APC and UPC.

These acronyms are referred to the form of the termination of the connector, so it can be:

PC: Physical Contact (blue color).

UPC: Ultra physical contact (Ultra Physical Contact).

APC: Angled Physical Contact (green color).

The form of completion is of great importance because it intervenes in the behavior of the fiber, especially the losses that may occur in the connection:

Loss of return or reflection: power of light that is reflected back to the source that generates it. These returns must be taken into account especially in systems with CATV since they can damage the laser light sources or cause interference or interruptions.

Insertion loss: It is the loss that is due to the same connection of the two fibers. Typical insertion losses are 0.15 to 0.5 dB per connector.

The SC / APC connectors are the ones that have a better performance in terms of return losses, because they offer values ​​higher than 65 dB, and it is due to their termination at an angle that avoids reflections to the source. For this reason, for installations with video by “overlay” it is convenient to always use SC-APC connectors.

The connectors used for the OLT are SC / PC (blue). SC-SCP – SC-APC patch cords are used if the rest of the network is built with SC-APC connectors.

The connectors for the ONT, (EG8245H, and EG8247H …) are always SC-APC (green).

An SC-APC should never be connected to an SC-SPC since attenuation and reflections are introduced. Visit Sopto for more details…