Optical fiber jumper is an indispensable connecting cable in optical fiber wiring. When purchasing optical fiber jumper, we will always see the indicators PC/APC/UPC, such as LC/UPC optical fiber jumper, FC/UPC optical fiber jumper, SC/APC fiber jumper, ST/PC fiber jumper, etc. What does PC/APC/UPC stand for? Does the SFP optical module match with PC/APC/UPC fiber optic jumpers?
PC/APC/UPC refers to different grinding methods of optical fiber connectors on optical fiber jumpers, and different grinding methods determine the quality of optical fiber transmission, mainly reflected in return loss and insertion loss.
| PC | UPC | APC |
| Physical Contact | Ultra Physical Contact | Angled Physical Contact |
| The most common grinding method for optical fiber connectors on optical fiber jumpers, the return loss of optical fiber jumpers using PC grinding is -40dB. | Evolved from PC, with better surface finish, the return loss is generally -50dB. | The end face is ground into an 8-degree angle, which can effectively reduce reflection, and the return loss is about -60dB. APC can only be connected with APC. Since the structure of APC is completely different from that of UPC, if the two connectors are connected with a flange, the fiber end face of the connector will be damaged. |
You can click here to learn more about the differences between PC/APC/UPC.
How to select PC/APC/UPC fiber jumpers for SFP optical modules?
As we all know, the SFP optical module has two transmission channel ports, one port is used to send signals, and the other port is used to receive signals. Usually, the transmission of signals needs to be realized through optical fiber jumpers. Is PC/APC/UPC fiber patch cords with different grinding types compatible with SFP optical modules? In fact, because the connection port of the SFP optical module is flat, it can only be connected to the fiber jumper of PC and UPC. If it is connected to the fiber jumper of APC, it will cause invalid connection or network failure.
In principle, PC/APC/UPC optical fiber connectors with three different grinding methods cannot be interconnected, but since the optical fiber end faces of PC and UPC are flat (with a slight bend) structures, the two can be compatible and interchangeable. There will be a problem with the quality of the polishing, but it will not cause any damage to the connector. Although SFP optical modules can be connected with PC and UPC optical fiber jumpers, in order to ensure the goodness of optical fiber links, it is recommended that you use SFP optical modules with UPC optical fiber jumpers.
The fiber end-face structure of APC and PC and UPC is completely different, so APC cannot be interconnected and compatible with them. If it is forced to connect, it will cause damage to the connector; if you want to connect APC and UPC/PC, you must connect the two through APC-UPC/APC-PC conversion fiber jumper. However, considering the waste of resources, difficult wiring and other reasons, it is not recommended that you do this. Therefore, it is best not to use APC fiber jumpers on the SFP optical module. Unless the manual of the SFP optical module says that APC fiber jumpers are allowed, it is recommended that you use UPC fiber jumpers.
Summary
All in all, PC and UPC fiber patch cords can be used on Ethernet devices such as fiber optic switches and used with SFP optical modules; APC fiber optic patch cords are mainly used for FTTx, passive optical network (PON) and wavelength division multiplexing (WDM), it is best not to use it with SFP optical modules. The specific selection depends on your network requirements.
