The fiber end is embedded in a 2.5 mm ferrule made of zirconia ceramic or stainless steel. The tip is then typically polished to produce a rounded surface, called “physical contact” polish. This surface profile means that when the fibers are mated they touch only at their cores, allowing transmission with low loss. The fibers are spring-loaded to control the force as the plug is screwed into the receptacle. A key prevents the fiber from rotating while the connectors are being mated.
Some manufacturers have several grades of polish, for example an FC connector may be designated “FC/PC” (for Physical Contact), while “FC/SPC” and “FC/UPC” may denote “super” and “ultra” polish qualities, respectively. Higher grades of polish give less insertion loss and lower back-reflection.
For applications requiring very low back-reflection, the fiber end-face is polished at an angle (the typical industry standard being 8°) to prevent light that reflects from the interface from traveling back up the fiber. Because of the angle, the reflected light does not stay in the fiber core but instead leaks out into the cladding. Angle-polished connectors only mate properly to other angle-polished connectors. Mating to a non-angle polished connector causes very high insertion loss. Generally angle-polished connectors have higher insertion loss than good quality straight physical contact ones. “Ultra” quality connectors may achieve comparable back reflection to an angled connector when connected, but an angled connection maintains low back reflection even when the output end of the fiber is unmated.
Angle-polished connections are distinguished visibly by the use of a green strain relief boot. The connectors are typically designated “FC/APC” (for Angled Physical Contact), or merely “FCA”.
- Complies with IEC 61754-13 and TIA 604-4-B, FOCIS-4 for intermateability.
- Low insertion loss and back reflection capability.
- Precision anti rotation key for mechanical stability.
- Nickel plated metal body corrosion resistant.