MT-RJ vs LC connector: which Small Form Factor connector to choose?

MTRJ is a Small Form Factor duplex connector.


It holds two fibers at the same time in a small body. Its body and ferrule are made of plastic and it has male and female versions that stay in place with metal pins.

The growing deployment of fiber optics in

  • Data Centers
  • Telcos
  • Wide Area Networks
  • Local Area Networks (LAN) and building backbones opened an issue about fiber connectors’ size.

Using big connectors such as ST and SC increased floor use which caused higher installation costs and made it difficult to expand connections.

So, What was the solution?

Small Form Factor (SFF) connectors were created as a solution. SFF connectors help reducing deployment costs and saving floor space for cables and equipment in fiber optic installations because they make it possible to put several fiber connections in the same space. In the late 90’s different types of SFF connectors were developed, but just two of them succeeded until the current days: MT-RJ and LC.

MT-RJ connector was developed by AMP and at its moment was advertised as the ultimate SFF connector. AMP used the MT ribbon connector design as an inspiration to create an inexpensive MT connector that could hold two fibers into a plastic ferrule.

LC connector is a small, low insertion and loss connector that was created by Lucent Communications in order to suit their customers’ needs. It is made from plastic and holds a single fiber into a ceramic or zirconia ferrule.

Two LC connectors can be put together into a duplex assembly and occupy the same space as a single SC would.

But which SFF connector to choose?

  • LC connectors deliver better Insertion Loss and Return Loss


Because its 125um ceramic ferrule offers a better connector-adapter-connector mating quality. Instead, MT-RJ ferrules are made from plastic and use metal pins to align the fibers.


Multimode Connectors

LC Duplex


Insertion Loss

0.3 / 0.5 dB

0.4 / 0.75 dB

Return Loss

-30 / -20 dB

-20 / -20 dB


  • It is easier to clean LC connectors because they allow to use traditional fiber cleaning. MT-RJ connectors are difficult to clean due to the alignment pins.

  • LC connectors can be spliced and installed in the field using the same methods as SC and ST, while MT-RJ connectors require two fibers to be installed/spliced at the same time, which could harm the overall performance.

  • The LC has become the preferred connector for transceivers with high rate applications because most manufacturers support LC interfaces and they are available from 10Mbps to 10Gbps applications.

    However, MT-RJ multimode connectors have a little support among transceivers and LAN equipment manufacturers, especially for 100BASE-FX interfaces.

Though LC is, obviously, the ultimate SFF connector, MT-RJ can still be used for some applications, especially in its multimode version.

To suit your application needs, we offer different types of MT-RJ patch cords such as OM2 MT-RJ-LC 50/125 and OM1 MT-RJ 62.5/125 such as other patch cord combinations.

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April 07, 2016 by
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