PC, UPC and APC are the three grinding methods for the inner ferrule of optical fiber connector. The ferrule of the optical fiber connector is the shell of the bare end of the optical fiber, which is used to connect with the transmitting end or receiving end of another optical fiber. When the connector is installed at the end of the optical fiber, the light will reflect back to the optical fiber and face the light source, thus affecting the signal transmission. In order to improve the transmission efficiency of optical fiber engineers, optical fiber ring is introduced.
What is a PC fiber optic connector?
PC optical fiber connector is polished by physical contact, which is the most common polishing type on om1 and om2 multimode fibers. In the design of PC optical fiber connector, there is a slightly cylindrical conical head, which is used to eliminate air gap.
What is UPC fiber optic connector?
UPC, or superphysical contact, evolved from PC connectors for better surface finish. UPC connectors rely on machine polishing, and the return loss is higher than PC connectors, which is close to - 50dB or higher.
What is APC fiber optic connector?
APC refers to angle physical contact. Different from UPC connector, the end face of APC connector is precisely ground and forms an angle of 8 degrees with the fiber cladding, which makes most of the return loss reflected into the cladding, which will not interfere with the transmission signal and damage the laser source.
PC vs UPC vs APC connector: what's the difference?
In terms of appearance, the main difference between PC, UPC and APC connectors lies in the end face. Although the end face of UPC connector is slightly curved, both PC and UPC optical fiber connectors are non angle polished, while the end face of APC optical fiber connector is 8 degrees and polished with micro sphere surface. Connector types can also be distinguished by the color of the connector. In general, the PC / UPC connector is blue and the APC connector is green. Take FS LC APC single-mode fiber jumper as an example, the connectors at both ends of the fiber are green, while LC UPC single-mode fiber jumper connectors are usually blue.
With the improvement of technology, the performance of APC connector is also improved, and the difference of insertion loss between APC and UPC fiber connector has been reduced. According to the industry standard, the return loss of PC, UPC and APC optical fiber connectors is about - 40dB, - 50dB and - 60dB or higher respectively. The higher the return loss and the smaller the reflection, the better the connector performance. Therefore, the performance of APC fiber connector is higher.
The UPC or PC fiber optic connector is a good choice for those areas where the return loss requirement is not high. PC connector is very suitable for telecom operator network, while UPC connector is widely used in digital TV, telephone and data system.
For those applications that need high-precision optical fiber signal transmission, APC connector with high return loss should be selected; for applications with less sensitive optical fiber signal, PC or UPC fiber connector can be selected.
