Fiber Optic Cable Connector: Types, End Faces & Uses
Mar 25, 2025
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In today's era of rapid information transmission, optical fiber communication has become the cornerstone of modern communication networks thanks to its high-speed, long-distance transmission capabilities. Fiber optic cable connector, as critical components of fiber optic communication systems, play a vital role. In this article, I will introduce different types of fiber optic cable connectors and fiber optic endfaces including their definitions,features and applications.
1. Mainstream Fiber Optic Cable Connectors and Applications
1.1 MPO (Multi-fiber Push-On)
Definition: MPO connectors are high-density, multi-fiber connectors designed to accommodate multiple fibers in a single interface, supporting parallel connections for 8, 12, or 24 fibers.
Features:
Features:
Maximizes space efficiency: Saves physical space and increases wiring density.
Scalability: Easily expands network capacity for future upgrades.
High speed: Supports 40G, 100G, and higher-speed networks.
Efficiency: Reduces installation and maintenance time.
Applications:
Applications:
Data centers: Used for high-speed data transmission and reducing cable clutter.
Telecom: Deployed in FTTH installations for increased bandwidth.
Broadcasting: Supports high-definition video streaming.
High-performance computing: Facilitates fast data transfer between servers.
Standard: Complies with IEC 61754-7, TIA/EIA-604-12, etc.
Standard: Complies with IEC 61754-7, TIA/EIA-604-12, etc.
1.2 LC Connector
Definition: Developed by Bell Labs, LC connectors use a modular latch mechanism similar to RJ-style connectors.
Features:
Features:
Compact size: Ferrule diameter is 1.25mm (half of SC/FC), enabling higher port density.
Easy operation: Push-pull latching simplifies insertion/removal.
Stable performance: Low insertion loss and high durability.
Applications: Dominates single-mode SFF applications and is growing in multimode use, commonly found in routers and ethernet switches.
Standard: Complies with IEC 61754-20, TIA/EIA-604-10, etc.
Applications: Dominates single-mode SFF applications and is growing in multimode use, commonly found in routers and ethernet switches.
Standard: Complies with IEC 61754-20, TIA/EIA-604-10, etc.
1.3 ST Connector
Definition: ST connectors feature a round shell with a bayonet coupling mechanism, commonly used in fiber patch panels.
Features:
Features:
Simple structure: Easy to install and maintain.
Reliable: Bayonet coupling ensures stable connections.
Widely used: Common in patch panels and fiber-optic converters.
Applications: Typically used in 10Base-F connections and fiber patch panels.
Standard: Complies with IEC 61754-2, TIA/EIA-604-2, etc.
Applications: Typically used in 10Base-F connections and fiber patch panels.
Standard: Complies with IEC 61754-2, TIA/EIA-604-2, etc.
1.4 FC Connector
Definition: FC connectors use a metal shell with a screw-on coupling, commonly found in the ODF (patch panels).
Features:
Features:
Durable and robust: Screw-on design ensures secure, dust-resistant connections.
Versatile: Supports PC/APC end faces for diverse applications.
Applications: Widely used in telecom networks, patch panels, and optical terminals.
Standard: Complies with IEC 61754-1, TIA/EIA-604-1, etc.
Applications: Widely used in telecom networks, patch panels, and optical terminals.
Standard: Complies with IEC 61754-1, TIA/EIA-604-1, etc.
1.5 SC Connector
Definition: Developed by NTT, SC connectors have a rectangular plastic housing with push-pull latching.
Features:
Features:
Cost-effective: Affordable and easy to operate.
Low loss: Stable insertion loss and high durability.
High density: Suitable for dense installations.
Applications: Common in routers, switches, and transmission equipment.
Standard: Complies with IEC 61754-3, TIA/EIA-604-3, etc.
Applications: Common in routers, switches, and transmission equipment.
Standard: Complies with IEC 61754-3, TIA/EIA-604-3, etc.
1.6 MU Connector
Definition: The world's most compact single-fiber connector (based on SC), developed by NTT.
Features:
Features:
High density: Uses 1.25mm ferrules for compact installations.
Variants: Includes MU-A (cable), MU-B (backplane), and MU-SR (module) series.
Applications: Used in cable/backplane connections and LD/PD modules.
Standard: Complies with IEC 61754-15, TIA/EIA-604-15, etc.
Applications: Used in cable/backplane connections and LD/PD modules.
Standard: Complies with IEC 61754-15, TIA/EIA-604-15, etc.
1.7 E2000 Connector
Definition: A push-pull latching connector with a built-in dust cap, designed for single-mode fibers.
Features:
Features:
Dense installations: Compact shell design.
Dust-proof: Integrated protective cap.
Applications: Ideal for high-density single-mode environments.
Standard: Complies with IEC 61754-18, TIA/EIA-604-18, etc.
Applications: Ideal for high-density single-mode environments.
Standard: Complies with IEC 61754-18, TIA/EIA-604-18, etc.
2. Fiber Optic End Faces: PC, UPC, APC
2.1 PC (Physical Contact)
Definition: A PC end face refers to the fiber connector end face that adopts physical contact. The end face is precision-polished to a slight curve, with the fiber core located at the highest point of curvature. This effectively reduces air gaps between fiber components, allowing the two fiber end faces to achieve physical contact.
Features: PC end faces are relatively simple to manufacture, cost-effective, and meet general data, video, and voice transmission needs with good stability and reliability.
Applications: Widely used in various fiber optic communication systems, such as data centers, local area networks (LANs), and metropolitan area networks (MANs). Standard connectors such as SC, FC, and ST typically adopt PC end face polishing.
Standard: The industrial standard return loss for PC end faces is -40dB.
Features: PC end faces are relatively simple to manufacture, cost-effective, and meet general data, video, and voice transmission needs with good stability and reliability.
Applications: Widely used in various fiber optic communication systems, such as data centers, local area networks (LANs), and metropolitan area networks (MANs). Standard connectors such as SC, FC, and ST typically adopt PC end face polishing.
Standard: The industrial standard return loss for PC end faces is -40dB.
2.2 UPC (Ultra Physical Contact)
Definition: UPC end faces are enhanced versions of PC end faces, featuring better polishing performance and surface smoothness, with a dome-like shape.
Features: UPC end faces offer higher return loss (typically close to -50dB or better), effectively reducing the impact of reflected light on signal transmission and improving signal quality and stability.
Applications: Widely used in scenarios requiring high return loss, such as telecom networks, cable TV networks, and data centers. UPC connectors are particularly suitable for 10G/25G SFP modules, providing lower insertion loss and higher return loss.
Standard: The industrial standard return loss for UPC end faces is -50dB.
Features: UPC end faces offer higher return loss (typically close to -50dB or better), effectively reducing the impact of reflected light on signal transmission and improving signal quality and stability.
Applications: Widely used in scenarios requiring high return loss, such as telecom networks, cable TV networks, and data centers. UPC connectors are particularly suitable for 10G/25G SFP modules, providing lower insertion loss and higher return loss.
Standard: The industrial standard return loss for UPC end faces is -50dB.
2.3 APC (Angled Physical Contact)
Definition: APC end faces feature an 8° angled design, which deflects light into the cladding at an angle rather than back to the light source, further reducing return loss.
Features: APC end faces offer the highest return loss (typically -60dB or better), minimizing interference from reflected light and enhancing signal stability and quality. APC connectors are usually green, making the angled end face visible to the naked eye.
Applications: APC end faces are widely used in scenarios demanding extremely low reflection loss, such as single-mode fiber systems, DWDM systems, and fiber sensors. They are also suitable for broadcasting and legacy CATV networks.
Standard: The industrial standard return loss for APC end faces is -60dB.
Features: APC end faces offer the highest return loss (typically -60dB or better), minimizing interference from reflected light and enhancing signal stability and quality. APC connectors are usually green, making the angled end face visible to the naked eye.
Applications: APC end faces are widely used in scenarios demanding extremely low reflection loss, such as single-mode fiber systems, DWDM systems, and fiber sensors. They are also suitable for broadcasting and legacy CATV networks.
Standard: The industrial standard return loss for APC end faces is -60dB.
3. Conclusion
Fiber optic cable connectors are devices that enable detachable connections between fibers, precisely aligning end faces to maximize light coupling while minimizing system impact. They significantly influence the reliability and performance of optical transmission systems. The fiber end face (e.g., PC, APC) refers to the physical design (flat or angled) of the fiber itself, often noted in combinations like FC/PC or FC/APC-where "FC" denotes the connector type, and "PC/APC" indicates the end face design.
