There are five commonly used single-core connectors for office and outdoor applications. Three of them (FC, SC, and LC) also come with the angled varieties, making the total number of choices eight. 8° angle are sometimes necessary to reduce surface reflection for some single-mode systems. For most applications (SM or MM systems), however, standard 0° versions (ST, FC, SC, and LC) are more than adequate for reflection performance. One needs to consult with media converter vendors to determine if angle is necessary. Keep in mind that angled connectors have higher loss than their non-angled counterparts.

“PC” stands for “physical contact” while “APC” stands for “angled physical contact”. In both cases, the connector surfaces are shaped like a dome with the apex perfectly centered at the fiber core. So when connected, the mating fiber cores are in perfect contact eliminating the air gap entirely. Therefore, index matching gel is not necessary for either PC or APC type of connectors. Contact with inert liquids such as petroleum based oils won’t have any adverse effect on the performance of the connectors. However, water should not come in contact with fiber surfaces over extended period.

FC, SC, LC, and ST all have very similar optical performance. So form and housing material factors are often the main consideration when choosing a connector type. ST is the most popular for field applications for both SM and MM fibers. FC is the distant second. They are both made out of metal (zirconia ferrules) and —