What is a fiber optic coupler and how to properly choose it?

The relevance of fiber optic couplers, also called adapters, is constantly eclipsed by connectors.

but the truth is that they are a critical element in fiber optic links and systems and play a serious role in the connection performance.

Why?

Because fiber optic couplers role is to join or mate connectors together and make it possible to connect cables between each other and into active equipment.

Look:

Connectors’ role is to precisely hold, secure and align the fibers into their ferrules. Couplers purpose is to accurately hold, secure and align the ferrules into their mating sleeves, bringing the ferrules together at the midpoint. 

What does this mean?

That the alignment precision characteristics between connectors’ ferrule and couplers’ mating sleeves define the interconnection assembly performance.

Usually, fiber optic couplers are used to connect the same style of connectors

• SC to SC
• ST to ST
• LC to LC

But there are some of them, called hybrid adapters, able to mate different styles of connectors, such as

• SC to ST
• SC to LC and so on

Commonly, most adapters are female and allow the connection between two cables in order to communicate from the distance through a direct connection.

But:

there also are male-female couplers, which are usually plug into a connector port of equipment.

SC coupler

SC couplers are available in simplex and duplex styles. Single mode UPC couplers are blue, multimode UPC are beige and single mode SC/APC couplers are green.

SC/APC couplers are one of the most reliable connection styles, which is why they are broadly used in

• FTTH deployments
• CATV
• LAN
• WAN applications.

LC coupler

LC connectors are one of the most popular small form factor connectors which is why, along with LC couplers, are widely used in high density applications.

LC couplers are also manufactured in blue for UPC single mode, beige for UPC multimode and green for APC single mode and in simplex and duplex style.

ST coupler

ST adaptors are manufactured in metal and plastic and, also, in simplex and duplex style for single mode, multimode and APC versions. They are used to link ST connectors and components.

Beyondtech manufactures and supplies a wide range of fiber optic couplers for several applications that comply with all international standards.