As fiber is becoming more popular in Ethernet network applications, users look for networking products which not only have built-in fiber ports but are also designed to save rack-space. Traditional ST and SC fiber transceivers are simply too bulky. The high-port density of copper RJ-45 connectors sets the standard for space utilization.

Since conserving rack-space is very important, fiber connectors known as Small Form Factor (SFF) transceivers are preferred due to their compact size and the flexibility to maximize the number of fiber optic ports in an Ethernet switch.

Today, there are over 25 million Small Form Factor connections installed. Out of these connections, over 5 million are MT-RJ connectors and about 20 million are LC connectors. The MT-RJ connectors are mainly used in multi-mode LAN connections and the LC connectors in WAN and MAN applications.  

The MT-RJ connector, based on an interface invented by NTT Corp, provides fiber connections in a space similar to an RJ-45. This connector terminates two fibers in one ferrule. In addition, the MT-RJ is known for its solid performance. To illustrate, insertion loss for the multi-mode MT-RJ connector is 0.2dB, much lower than the maximum of 0.75dB that TIA/EIA-568-B.3 allows.
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MT-RJ SFF Transceivers 
(2 ports shown)

 LC SFF Transceivers
(2 ports shown)

With proven field applications, multi-vendor standards for interoperability, and port density matching the RJ-45 copper, SFF connectors provide practical solutions for Ethernet fiber connectivity.