Fiber optic jumper is an indispensable connection line in fiber optic cabling. When choosing fiber optic jumper, we always see the words PC/APC/UPC, such as LC/APC fiber jumper, FC/APC fiber jumper, SC/PC fiber jumper, ST/UPC fiber jumper, etc., so do you know what PC/APC/UPC stands for?
What is PC/APC/UPC?
PC/APC/UPC refers to different grinding modes of fiber optic connectors on fiber optic jumper lines, and different grinding modes determine the transmission quality of fiber, mainly reflected in return loss and insertion loss. So what's the difference between these three grinding methods?
1. What is a PC?
PC (Physical Contact) is the most common grinding method of fiber optic connector on fiber optic jumper, which is widely used in telecom operators' equipment. Although the end face of the fiber connector looks flat, it is actually slightly bent and polished, and the highest point of bending is the core center, which can effectively reduce the air gap between the fiber assemblies. Under normal conditions, the return loss of the fiber jumper using PC grinding mode is -40db.
2. What is UPC?
The UPC (Ultra Physical Contact) is an evolution of the PC that optimizes the end finish for better surface finish. UPC, like PC, has the highest bending point at the center of the fiber core, but the UPC's return loss is higher than PC's, typically at -50db (or even higher). It is commonly used on Ethernet network devices (such as ODF fiber distribution racks, media converters, and fiber optic switches), as well as telephone systems.
3. What is APC?
APC (Angle Physical Contact) is the latest technology of fiber end grinding. The Angle grinding method of 8 degrees is adopted to make the end grinding more accurate and effectively reduce reflection. The return loss is about -60db. APC is generally used for optical RF applications in high wavelength ranges such as CATV.
What's the difference between PC/APC/UPC?
After the above detailed introduction of PC/APC/UPC, you will find that PC/APC/UPC has differences in terms of end face, return loss, application, etc.
PC and UPC are both planar interface types. PC is one of the earliest grinding methods with poor return loss. UPC is based on PC structure evolution, its return loss is better than PC; APC is a grinding method with an 8-degree Angle on the end surface, which can effectively reduce reflection. Return loss is better than PC and UPC, and it is more suitable for high bandwidth and long distance links.
Note: return loss (i.e., reflection loss) refers to the reflection caused by impedance mismatch in the optical fiber link. It is the reflection of a pair of lines themselves. The reflected light of this percentage is usually expressed as -dB, and the higher the value, the better.
