- Brian
Harper Ross
Answered on 3:17 am
APC and PC/UPC are two types of polish styles for the ferrules inside the optical connectors. The ferrule is the housing for the exposed end of a fiber, designed to be connected to another fiber, or into a transmitter or receiver. The polish style affects the quality of the signal transmission and the return loss of the connector.
APC stands for Angled Physical Contact. It means that the ferrule endface is polished at an 8° angle, which causes the reflected light to reflect at an angle into the cladding instead of straight back toward the source. This reduces the return loss and improves the performance of the connector. APC connectors are usually green in color.
PC stands for Physical Contact. It means that the ferrule endface is polished with no angle but with a slight curvature for better core alignment. UPC stands for Ultra Physical Contact. It is an improvement of the PC polish with a finer surface finish and a lower return loss. PC and UPC connectors are usually blue in color.
Different applications may require different polish styles depending on the sensitivity to return loss and the wavelength range of the signal. Generally, APC connectors are preferred for single-mode fibers, especially for higher wavelengths (above 1500 nm) and longer distances. PC and UPC connectors are more common for multimode fibers and shorter distances.
Some examples of optical connectors that use APC polish are LC/APC, SC/APC, FC/APC, E2000/APC, etc. Some examples of optical connectors that use PC or UPC polish are LC/PC, SC/PC, FC/PC, ST/PC, MTRJ/PC, etc.
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