Often times when installing a fiber, you find yourself trying to select the most efficient fiber connector types for the application you are dealing with. JM Test Systems is here to ensure that you select the connector that will perform best for your needs. This blog post will break down the most common fiber connector types and explain their pros/cons, so that you can properly determine your selection of which connector you would like to use.
A fiber connector is also referred to as a “termination” and enables you to quickly connect/disconnect the fiber cables. Many fiber connector types have a spring-loaded connection to ensure that there is a constant force that is mating the two fibers together to confirm that you have a good clean connection for the pulse to go through. These spring-loaded connections also pull their weight by eliminating any air gaps between the connectors. An air gap will quickly rob the light transmission of making its way from fiber to fiber.
Typically, there are three main components to the construction of a connector.
- The Boot
- The Body
- The Ferrule
Ferrules are most commonly made of a material called zirconia. In the early days of connector manufacturing, the ferrules were constructed of stainless steel. Zirconia offers lots of advantages over other materials such as:
- Free from cracks, chips, or imperfections
- Because the grain is smaller on Zirconia, it will have a smoother finish
- The thermal expansion coefficient is very close to that of fiber
- A very high impact resistance
- A high modulus of elasticity
Today, we will go over the ST, FC, SC and LC styles. We will also touch upon the MTP/MPO connections.
ST Fiber Connector Types
These connectors use a 2.5mm ferrule that is mounted on the inside of the housing. This is an older style connector but is still commonly used in multimode applications.
- The ST connector, while older, is still commonly in use in today’s fiber installations due to it being extremely easy to install and its relatively low cost compared to some other connectors. This connector has a keyed “slot” on the end of the connector that helps keep it tightly mated to the fibers and in alignment when they are decoupled and recoupled.
- ST Connectors have a round shape to them and are not as compact as more modern square body connections. Also, with this being a spring-loaded connection, the installers must push the connector with quite a bit of force and turn the nut to use these connectors. If there is a tray with lots of connections this can get tedious as it may become hard to get into the tight spaces to decouple/recouple the connectors.
SC Fiber Connector Types
The SC connector was invented to directly replace the ST connectors and, as a result, has become one of the most common fiber connectors in the world. Similar to the ST connector, this SC style also utilizes a 2.5mm ferrule.
- The SC connector is what is called a non-optical disconnect connector. This term means that once the connector has been installed, any pushing or pulling on the jacket of the cable will not cause the ferrule to disconnect, which is a prevalent problem with the ST model connectors. This ensures that the signal is not to be interrupted. Sometimes with the ST connectors, when they are pulled back, the spring mechanism will slam the fibers together. An SC connector can alleviate these problems.
- The square shape of these connectors offers a more compact design which in turn means that more of these connectors can be installed in a smaller footprint of a space. Sometimes there just is not enough room for the pull and twist connectors and that is where the SC connector becomes a life saver.
- SC connectors are perfectly suited for datacoms and telecoms.
- The main disadvantage of and SC connector is although its square body is easier to insert/take out, the body is larger than the LC connector which means it will take up more room than its newer cousin.
FC Fiber Connector Types
The FC connector also utilizes a 2.5mm ferrule. This connector shares a round profile like the ST connectors we reviewed but instead of coming equipped with a spring-loaded twist lock mechanism, this connector has a threaded connection.
- Like the SC connector, the FC connector also has a non-optical disconnect advantage. Because this connector threads onto a connection, you can be sure that this connector will stay stable and mated to its connection, even during rougher environments.
- Very similarly to the ST, this connector can be hard to grab and twist to thread or unthread from a connection if there are lots of connectors in one receptacle.
LC Fiber Connector Types
LC Connectors were invented by Lucent Technologies (hence the LC name). This is a member of what is referred to as the small form factor (SFF) line of connectors. These SFF connectors were initially invented to fill a need for large fiber count applications. In some installations there are dozens of connectors being plugged in and these connectors make life much easier. The LC connector uses a 1.2mm ferrule and has about half the footprint size of the other connectors we have reviewed. It does share the same non optical disconnect as the SC and FC share.
If for some reason you are looking to switch from an SC, ST or FC connector there are some tools and adapters that can be used. Another plus for this connector is that the LC duplex connections have the same footprint as RJ45 connectors.
- You can quickly convert these instruments from a simplex connector to a duplex connector with the use of a clip. They are low loss connectors and are also pull proof. LC connectors can quickly be terminated and have a couple different methods to achieve that. The SFF design makes this the perfect connection for a high-density application, which is why this is the connection of choice for networking and transceivers.
- The SFF design makes it hard to grasp as it is so tiny and often in a densely populated application. There are LC extraction tools that can help with this. It is probably a good idea to order an extraction tool when ordering this type of connector.
MTP/MPO Fiber Connector Types
These connectors are used for ribbon cable. In single mode use these will typically get about .25dB loss and about .20dB loss in multi-mode. These are also available in the smaller 8 fiber connectors in this configuration. Single mode ferrules are angled at 8°. This is mostly used in very high-density applications with ribbon cable to reduce the connector space that may be required.
- MTP connectors are usually considered a high-performance option while MPO are better for mechanical uses.
- MTP connectors are equipped with a housing that is removeable so you can change, re polish or even change the gender of the connection from male to female.
- MPO/MTP connectors combine 8, 12 or 24 fibers into one single and compact interface. They can put this amount of cable in the same space an SC connector would take up. This very effectively saves rack space on a high-density rack.
- An MPO/MTP connector is not the easiest to clean on account of there being so many fibers in one connection.
When you rent fiber optic test equipment, such as an OTDR or OLTS with JM Test Systems, you get the added benefit of being able to pick and choose the launch cables or patch cords that fit your application. We also supply interchangeable input and output port adapters with every fiber tester to support SC, LC, ST and in some cases, FC style connections. If JM Test Systems can help you in any way with calibration, sales, rental or almost anything to do with fiber optic applications please give us a call at 318-443-5589 or send us a quick message.
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