Uploaded by HYC Co., Ltd

Fiber Optic Patch Cables PC, APC or UPC

Fiber Optic Patch Cable PC, APC or UPC
To make better contact between the ends of the two fibers, the ferrule end faces of the fiber
optic patch cable is usually polishing into different structures. Standard polishing methods are PC,
APC, and UPC. PC/APC/UPC represents the front end structure of the ceramic ferrule.
Different fiber end face finishes
PC (Physical Contact).The two end faces are polished to be slightly curved or microspherical, and
the fiber core is at the highest point of the bending. This eliminates the air gap and forces the
fibers into physical contact.
UPC (Ultra Physical Contact) is based on the PC to optimize the end face polishing and surface
finish, the end face looks more dome-shaped. The end face of the UPC connector is not entirely
flat, and there is a slight arc to achieve more accurate connecting.
APC (Angled Physical Contact). The end face of APC is usually polishing into an 8-degree angle.
The 8 ° angled bevel makes the fiber end face tighter and reflects light through its beveled
angle to the cladding instead of returning directly to the source, providing better connection
Different physical appearance
The APC fiber optic connector is usually green. UPC/PC connectors are easily identified by their
Insertion loss and return loss
Different polishing styles determines the quality of optical fiber, which results in different
performances regarding the connector's insertion loss and return loss. Insertion loss refers to the
signal loss caused by the connector or cable. In general, the typical insertion loss of PC, UPC, and
APC connectors should be less than 0.3dB. Compared with APC connectors, UPC connectors are
usually easier to achieve low insertion loss due to the smaller air gap. Insertion loss can also be
caused by a tiny particle of dust trapped between the connector end-faces. A single dry debris
particle could even damage the fibers and ferrules.
Return loss, also known as reflection loss, is a parameter representing the signal reflection
performance. Usually expressed in negative dB value, the higher the value of the setting, the
better. The end faces of APC connectors are beveled, so the return loss of APC connectors is
usually better than UPC connectors. In general, the return loss of the PC fiber cable is -40dB. UPC
return loss is higher relative to PC, generally at -55dB (or even higher). APC industry-standard
return loss is -65dB. With the UPC connector, any reflected light is directly reflected back to the
light source. The beveled end face of the APC connector allows the reflected light at an angle into
the cladding instead of reflecting it directly to the light sources. This is the main factor that
causes the return loss to differ.
PC is the most common grinding method for optical fiber connectors, which is widely used in
telecommunication operator equipment. UPC is commonly used in Ethernet network equipment
(such as ODF fiber distribution frames, media converters and fiber switches, etc.), digital, cable
television and telephone systems. APC is generally used in optical radio frequency applications
such as CATV, and also in passive optical applications, such as PON network structures or passive
optical local area networks.
Connector connections need to be in the same end face structure; for example, APC and UPC
cannot be mated together , because doing so will resulting in poor connector performance.
However, the end faces of PC and UPC fibers are flat, and the difference is in the quality of
grinding. Therefore, the mixed connection of PC and UPC will not cause permanent physical
damage to the connector.
HYC has 19 years of experience in research and development of essential passive components for
optical communications, supplying all kinds of fiber connectors and fiber patch cords for various
specifications. HYC Co., Ltd(HYC)is, a national Hi-tech optoelectronics company engaged in R&D,
manufacture, and marketing of fiber optical products. Providing professional products and
services for fiber connectivity, WDM, PLC splitter, MEMS optical switch, and high-density
datacom cabling. HYC products and solutions widely applied in 4G/5G, Data Center and Cloud
Computing industry, etc.
[email protected]