- 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.
People Also Ask
What Is a DAC Cable? Direct Attach Copper Explained
A DAC cable, or direct attach copper cable, is a fixed-length twinax copper cable assembly with transceiver-style connectors permanently attached to both ends. It connects servers, switches, and storage devices over short distances without requiring separate optical transceivers. Because it carries electrical signals over copper rather than converting them to
Optical Interconnect Quality Management for AI Clusters
As AI infrastructure evolves toward increasingly large GPU clusters, optical interconnect reliability is becoming a critical factor in overall computing performance. Modern AI data centers rely on thousands or even hundreds of thousands of optical links connecting GPUs, switches, NICs, and storage systems. A single unstable link can introduce retransmissions,
CWDM Wavelengths: The Complete 18-Channel Chart
The CWDM wavelength grid covers 18 nominal center wavelengths from 1271 to 1611 nm, spaced 20 nm apart under ITU-T G.694.2. Many conventional CWDM links use the eight higher-wavelength channels, from 1471 through 1611 nm, because they avoid the water-peak region that can cause high attenuation on older single-mode fiber.
102.4T NPO Switch Design: Near-Package Optics for AI Scale-Up Networks
As AI clusters grow from hundreds to thousands of accelerators, traditional electrical and pluggable optical interconnects face increasing challenges in bandwidth density, power consumption, and signal integrity. A 102.4T NPO switch (Near-Packaged Optics switch) addresses these limitations by placing optical engines close to the switching ASIC, shortening high-speed electrical paths and
Related Articles
800G SR8 and 400G SR4 Optical Transceiver Modules Compatibility and Interconnection Test Report
Version Change Log Writer V0 Sample Test Cassie Test Purpose Test Objects：800G OSFP SR8/400G OSFP SR4/400G Q112 SR4. By conducting corresponding tests, the test parameters meet the relevant industry standards, and the test modules can be normally used for Nvidia (Mellanox) MQM9790 switch, Nvidia (Mellanox) ConnectX-7 network card and Nvidia (Mellanox) BlueField-3, laying a foundation for
What Is a DAC Cable? Direct Attach Copper Explained
A DAC cable, or direct attach copper cable, is a fixed-length twinax copper cable assembly with transceiver-style connectors permanently attached to both ends. It connects servers, switches, and storage devices over short distances without requiring separate optical transceivers. Because it carries electrical signals over copper rather than converting them to
Optical Interconnect Quality Management for AI Clusters
As AI infrastructure evolves toward increasingly large GPU clusters, optical interconnect reliability is becoming a critical factor in overall computing performance. Modern AI data centers rely on thousands or even hundreds of thousands of optical links connecting GPUs, switches, NICs, and storage systems. A single unstable link can introduce retransmissions,
CWDM Wavelengths: The Complete 18-Channel Chart
The CWDM wavelength grid covers 18 nominal center wavelengths from 1271 to 1611 nm, spaced 20 nm apart under ITU-T G.694.2. Many conventional CWDM links use the eight higher-wavelength channels, from 1471 through 1611 nm, because they avoid the water-peak region that can cause high attenuation on older single-mode fiber.
102.4T NPO Switch Design: Near-Package Optics for AI Scale-Up Networks
As AI clusters grow from hundreds to thousands of accelerators, traditional electrical and pluggable optical interconnects face increasing challenges in bandwidth density, power consumption, and signal integrity. A 102.4T NPO switch (Near-Packaged Optics switch) addresses these limitations by placing optical engines close to the switching ASIC, shortening high-speed electrical paths and
CWDM SFP Guide: Wavelengths, Channels, and Reach
The number on the CWDM SFP label is not the number on the mux port. A module arrives marked 1470 nm. The port it needs to reach is labeled CH11. Neither label mentions the other, and nothing in the box explains that they describe the same channel. That single gap
CWDM Mux Demux: Channels, Insertion Loss, and Selection Guide
The 18-channel CWDM mux demux can look like the safest purchase: room to grow, one part number, and no second trip to procurement. Then the link budget arrives. An 18-channel unit may add around 5.0 to 5.4 dB of insertion loss, while an 8-channel unit may add around 2.4 dB.