A PC (Physical Contact) fiber optic connector end face features a slightly curved surface that allows direct contact between fiber cores, reducing air gaps and enabling reliable optical signal transmission.

Structure and Design

The PC end face is polished to a slight convex curvature, with the fiber core positioned at the highest point of the curve. This design ensures that when two fibers are connected, their cores make physical contact, minimizing the air gap between them and improving light coupling efficiency. The curvature is subtle, giving the appearance of a nearly flat surface while still achieving physical contact .

Performance Characteristics

• Return Loss: PC connectors typically have a return loss of around -40 dB, which is sufficient for general data, video, and voice transmission .
• Insertion Loss: The insertion loss is generally low, often less than 0.3 dB, depending on connector quality and cleanliness .
• Comparison: PC connectors are older technology and have been largely replaced by UPC (Ultra Physical Contact) connectors, which offer a more domed polish and higher return loss (_{-50 dB), and APC (Angled Physical Contact) connectors, which have an 8° angled end face to reduce back-reflection (}-60 dB), .

Applications

PC connectors are widely used in telecom networks, LANs, MANs, and data centers where moderate return loss is acceptable. They are compatible with standard connector types such as SC, FC, and ST . While UPC and APC connectors are preferred for high-speed or high-reflection-sensitive applications, PC connectors remain cost-effective and reliable for general optical communication needs.

Summary

The PC type end face is a fundamental fiber optic connector design that ensures physical contact between fiber cores, reducing signal loss and maintaining stable transmission. Its simplicity and cost-effectiveness make it suitable for many standard optical communication systems, though higher-performance UPC and APC connectors are used in more demanding scenarios .