Fiber optic PC connector

A PC (Physical Contact) fiber optic connector is a type of connector where the fiber ends are polished to make direct contact, reducing the air gap and improving signal quality.

Overview of PC Connectors

A PC fiber connector stands for Physical Contact. It was developed in the 1980s to improve upon the original flat fiber connectors, which had significant air gaps between fiber ends, causing high optical return loss (ORL) and signal degradation . In a PC connector, the fiber end faces are slightly convex, allowing the cores of two fibers to touch directly when mated. This reduces back reflection and improves signal transmission compared to flat connectors .

Optical Performance

The typical return loss for a PC connector is around -40 dB, which is higher than the original flat connectors but lower than more advanced types like UPC (-50 dB) and APC (-60 dB), . While PC connectors are still functional, they are gradually being replaced by UPC (Ultra Physical Contact) connectors, which offer better surface finish and lower return loss, and APC (Angled Physical Contact) connectors, which further reduce back reflection by angling the ferrule end face .

Applications

PC connectors are used in both single-mode and multimode fiber networks, including telecommunications, data centers, and digital TV systems . They are suitable for general-purpose connections where extremely low return loss is not critical. For high-performance applications, UPC or APC connectors are preferred.

Comparison with Other Connectors

• Flat connectors: Older style, high return loss (~-14 dB), largely obsolete.
• PC connectors: Slightly convex end face, return loss ~-40 dB, improved over flat connectors.
• UPC connectors: Enhanced PC with better polish, return loss ~-50 dB, widely used in modern networks.
• APC connectors: Angled end face, return loss ~-60 dB, ideal for RF video, GPON, and high-precision applications .

Key Takeaways

PC fiber connectors were a significant improvement over flat connectors, providing direct physical contact between fiber cores to reduce signal reflection. While still in use, they are largely superseded by UPC and APC connectors in modern high-performance fiber optic networks due to their superior return loss and optical performance .