When encountering fiber optic connectors in daily life, we will see descriptions such as FC/UPC, FC/APC, SC/UPC, LC/APC, and so on.
From the above introduction, we know that FC, SC, LC refer to the types of fiber optic connectors. What do the letters UPC and APC
after the slash mean-- Grinding type: In order to ensure better contact between the end faces of two optical fibers, the plug end
face of the fiber optic connector is usually ground into different structures. The common types of fiber end face grinding are PC, UPC,
and APC.
PC (Physical Contact) refers to the spherical shape of the end face of the fiber optic connector plug. Currently, PC has been basically replaced by UPC, and the commonly used PC end face usually refers to the grinding type of UPC. UPC (Ultra Physical Contact) is a
type of physical contact. UPC is based on PC and further optimizes the end face polishing and surface smoothness. The end face
looks more dome shaped, and the return loss index is better than PC, usually up to -50dB or more.
PC and UPC grinding type fiber optic connectors are commonly known as "flat heads".
APC (Angular Physical Contact) refers to physical contact at an angle. The fiber end face is usually ground into an 8 ° slope, allowing
the reflected light to be reflected into the cladding through the slope angle, thereby minimizing back reflection to the greatest extent possible. Under normal circumstances, the return loss can reach over -60dB.
APC grinding type fiber optic connectors are commonly known as "angled heads".
