Fiber Connector Types and How They Work

May 18, 2017 at 8:00 AM


There is no shortage of options available when it comes to fiber optic cables. We’ve discussed the different fiber terms, what they mean and how to read them. Now, we’ll take a closer look at fiber connector types.


There are numerous fiber optic connectors on the market today. The most common connector types are LC, SC, and ST styles.


ST – This connector type is still widely deployed in fiber networks. These connectors employ a bayonet style mount and cylindrical 2.5 mm ferrule that’s usually made of ceramic, but sometimes is constructed of metal or plastic. ST connectors are spring-loaded, so they must be properly seated/aligned to avoid high-loss.


SC - These snap-in connectors feature a 2.5 mm ferrule that keeps them secure in the port. The snap-in design latches with a simple push-pull motion. These connectors are available in simplex and duplex configurations.


FC – These connectors also use a 2.5 mm ferrule. They screw-in to connect firmly, though the key must be properly aligned in the slot before tightening. FC connectors were the most popular connector type for many years, but have largely been replaced by SC and LC connectors.


MT-RJ – These duplex connectors house both fibers in one polymer ferrule. They use pins for alignment and are offered in male and female versions. This connector type is not very widely used.


LC – These connectors use a standard ceramic ferrule. What sets theses connectors apart from other styles is that they are small form factor connectors that use a 1.25 mm ferrule and are half the size of SC connectors. LC connectors have been the most widely used interfaces in networking equipment over the past 10/15 years due to their small size.


All of these connectors are available in both Single mode and Multimode versions. ST, SC and FC connectors use the same 2.5 mm ferrule size, so they can me mixed and matched when connected using hybrid mating adapters as shown here:






There are three optional polish types that can be applied to fiber connectors: physical contact (PC), ultra-physical contact (UPC) or angled physical contact (APC). Each polish type provides a different level of back reflection, which is a measurement, in decibels, of the light reflected off the end of a fiber connector, and can be critical in some applications.


Click here to watch our video on fiber optic connector types.


For an in depth look at fiber connector colors, check out this blog post.


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