A Complete Guide to Fiber Optic Adapter

What are fiber optic adapters?

Fiber optic adapters, also known as fiber optic couplers, are designed to connect two fiber optic cables or fiber optic connectors in the fiber optic lines. Due to superior, stable, and reliable performance, they’re widely used in telecommunication, Optical Distribution Frames(ODFs), fiber optic equipment, optical fiber instruments, measuring appliances, etc.

According to the number of fibers to be linked, they come in versions of simplex, duplex, and sometimes quadplex. The singlemode adapters offer more precise alignment of the tips of the ferrules of the connectors. You could use singlemode adapters to connect multimode cables, but you shouldn’t do inversely, as it may misplace the tiny singlemode fibers and cause a loss of signal strength.

Types of fiber optic adapters

Because the fiber optic adapters are inserted into fiber optic connectors or cables, their panel shapes need to be in accordance with them. There are varieties of fiber optic connectors interfaces, so fiber optic adapters could also be classified as several types, including FC, SC, ST, LC, MTRJ, MPO, etc. Generally, they’re square, rectangular, or round in shape.

FC Fiber Optic Adapter

The name “FC” stands for “ferrule connector” or “fiber channel.” It originated from JP NTT. Recognized as one of the most popular singlemode connectors, The FC connectors are simple in structure and easy to operate and manufacture. Initially, some of these connectors used ceramic inside stainless steel ferrules. Now the FC also uses a 2.5 mm ferrule made of zirconia ceramic. Once due to the vulnerability of the fiber end face to the dust, it would produce Fresnel reflection and a degraded return loss performance. But as time goes by, its insertion loss and return loss performance have been greatly improved.

Typically, It can be divided into square, oval, round, and rectangle types in single-mode and multimode versions.

SC Fiber Optic Adapter

Also developed by Japan NTT, SC Connectors and Adapters have a push/pull snap-in design. It is composed of a plastic housing with φ2.5mm OD Zirconia Ferrules. It has a rectangular shape with a 2.5 mm ferrule. It’s easy to plug and unplug with low insertion loss variations, high compressive strength, and high installation density. Due to its excellent performance, ease of operation, and low price, it is increasingly used in network applications, particularly single-mode fibers. Duplex versions are also available.

ST Fiber Optic Adapter

It’s the most popular connector for multimode fibers, usually used within buildings. It contains a spring-loaded bayonet mount and a long cylindrical 2.5 mm ceramic ferrule to ensure long-term stable mechanical and optical properties.

LC Fiber Optic Adapter

Designed by Lucent Technologies, The LC Connectors and Adapters have been the most popular ones in the singlemode Small Form Factor (SFF), for their pins and sleeves are half the sizes used for standard SC, FC, etc., at 1.25mm OD Ferrule. So these connectors are compact, high density, and high performing at a low cost.

MT-RJ Fiber Optic Adapter

MT-RJ Fiber Optic adapter connects two duplex MTRJ fiber optic cables. It occupies approximately the same space as a simplex SC adapter, offering more user-friendly characteristics in high-density applications.

MU Fiber Optic Adapter

Also developed by JP NTT, the MU(MINIATURE UNIT ) connectors and adapters are the smallest ones, at least half the size of the standard SC adapters. The MU adapter provides double port density and the same performance as SC connectors and adapters.

MTP/MPO Fiber Optic Adapters

MTP/MPO Fiber Optic Adapters link MTP or MPO cables or connectors together. Each MTP/MPO cable has up to 12 fibers, and each MPO/MTP connector has up to 72 fibers.

MPO/MTP adapters don’t distinguish between singlemode and multimode compared to SC fiber adapters. They have respective colors for singlemode (blue), singlemode APC (green), multimode OM3 (aqua), and non-particular medium(black). Widely used in trunk cabling, ODFs in building rooms, MPO / MTP cassette modules, etc.

Bare fiber adapter

The bare fiber adapter temporarily connects the bare fiber, providing a provisional connection to test bare fiber, fiber on the reel, and fiber before and after installation. Contained in the durable aluminum-alloy housing, it easily permits any test and detection.

FEATURES and Specifications

Fiber optic adapters usually have ceramic sleeves, fitting for both singlemode and multimode fiber optic connections. Most of them could connect the cables or connectors on both sides. Some only plug into a port on a piece of equipment.

Features:

Low insertion loss, high return loss
Good compatibility
High precision of mechanical dimensions
High reliability & stability
Ceramic or Bronze Sleeve
PCAPCUPC optional
Simplex / Duplex/Quadplex

Specifications:

What to consider when choosing a fiber optic adapter

Given the diversity of fiber optic adapters, when you want to choose one specific kind of fiber optic adapter, you should know that:

The fiber adapters usually link with the same fiber connector type, with a square, rectangular, or circular interface. However, the hybrid fiber adapter could connect different connectors, thus linking two types of fiber patch cords together. So you should purchase a particular kind of fiber adapter following the sort of cable/connector to be connected.
Remember that ceramic-made fiber optics adapters have long been recognized as much better than metal-made ones. Compared to metal, the crystal structure of the ceramic is rigid and does not deform over time.

Cleaning methods

Typically, there are two main cleaning methods, i.e., contact and non-contact cleaning.

Contact cleaning method

As the end face of the fiber optic is sensitive to dust, we should use a dust-free wiping paper or cleaning cloth with sewage alcohol to wipe its end face.
Also, you can use the strong adhesive on the wiping tape installed in the rollable casing to stick the dirt on the end face of the fiber optic connector.
You can insert the fiber-optic cleaning pen into the ceramic sleeve of the adapter. With just a push, you can clean the end face of the ferrule.

Non-contact cleaning method

Sprinkle the ultrasonic cleaning liquid on the end face of the fiber connector.
After spraying the cleaning liquid onto the end face of the fiber connector, use the high-pressure gas to blow-dry it.

Summary

Above is the basic knowledge of fiber optic adapters. If you read it through but still have some questions, you may leave a comment, and we’d like to reply as soon as possible.