Patch cord APC and patch cord UPC are both single mode fiber patch cords, and they are widely used for termination and patching single mode fiber optic cable in FTTH network. Their main difference are the fiber optic connector end face polishing method difference. UPC is Ultra Physical Contact, APC is Angled Physical Contact. The different end face design result in different in optical performance and application scenarios.
- Read More:
- Optical Fiber End Face Grinding and Polishing Methods: PC, UPC, and APC.
- Fiber Optic Patch Cables, Fiber Patch Cords
- Fiber patch cord types and functions
End Face Structure and Appearance Differences
Patch Cord UPC
- End Face Polish: Flat, slightly convex spherical design with no angles.
- Color Identification: Blue housing (universal standard).
Patch Cord APC
- Endface Polish: 8° angle polishing deflects reflected light away from the fiber core.
- Color: Green outer shell (universal standard).
Optical performance comparison
| Parameters | Patch cord UPC | Patch cord APC |
| Return loss | ≤ -50 dB | ≤ -60 dB |
| Reflection control | Partially reflected light returns to the fiber core | Reflected light is eliminated by directing it into the cladding |
| Insertion loss | Low (typical applications) | Similar (precise docking required due to angles) |
Key mechanism: The patch cord APC’s 8° bevel refracts reflected light into the cladding, avoiding interference with the light source signal.
Patch Cord Application Selection
Patch cord UPC is suitable for general digital communications such as Ethernet and routers, short-distance transmission, and environments that are not sensitive to reflections.
While patch cord APC is mandatory in the following scenarios:
- Analog signal transmission: For example, in broadcast and television CATV systems, reflections can directly affect image quality.
- High-speed PAM4 modulation systems (such as 400G optical modules): Reflections can misinterpret multi-level signals (01/00).
- Long-haul/high-sensitivity links: Lasers are susceptible to damage from reflections.
Fiber Optic Patch Cord Compatibility and Precautions
Do Not Mix:
The angled endface of an APC patch cord does not align with the flat surface of a UPC patch cord. Mixing these connectors will result in a significant increase in insertion loss (>3dB).
Durability Difference:
The patch cord UPC’s endface is susceptible to wear after repeated insertion and removal, and return loss may deteriorate to -40dB. The patch cord APC’s structure is more stable.
Cleaning Requirements:
Due to the angled design of the APC patch cord, dust is more likely to affect the optical path, requiring frequent maintenance. We can provide supporting toolsets such as a fiber optic cleaning pen, cleaning sticks, kimwipes, and an endface fiber microscope for on-site push-to-connect cleaning and inspection.
Conclusion
APC patch cord achieves ultra-low reflection through physical tilting and is designed for high-sensitivity systems; UPC patch cord is lower cost and suitable for general digital communications. Selection should be based on a comprehensive consideration of signal type, distance, and reflection tolerance.
APC UPC Patch Cord FAQ
How can I distinguish between UPC and APC patch cords?
If the fiber patch cords use the same connector type, then the UPC connector housing is blue, while the APC connector housing is green.
What is the purpose of the 8° bevel on the APC patch cord?
The 8° bevel on the APC patch cord deflects reflected light toward the cladding, preventing interference with the light source signal.
Is there a significant price difference between UPC and APC patch cord?
Currently, because patch cords are mass-produced and widely used, costs have bottomed out, and the prices of UPC patch cords and APC patch cords are very similar.
Can you offer PC patch cord?
Yes, PC is one of 3 types of endfaces:UPC, PC, APC. UPC APC endfaces are for single mode patch cord connectors, while PC enface is for multimode patch cord connectors.
