PC vs APC Connector for Fiber Optic Fixed Attenuator, Which One to Use?
When buying SC APC fixed attenuator, LC APC fiber attenuator or FC PC optical attenuator, many system integrators are confused about PC (UPC) and APC polishing difference. The polish directly decides return loss and signal stability of your optical fixed attenuator.
What is PC / UPC and APC Polishing?
PC/UPC: Flat spherical end face, typical return loss around 40–50dB,
suitable for 1310/1550nm telecom transmission, data center links.
APC: Angled 8-degree end face, reflection is diverted away from fiber core,
achieving higher return loss performance, preferred for CATV, PON FTTH networks.
Our OAT-HF high return loss optical fixed attenuator supports both PC and APC polishing for SC, LC, FC connectors.
Application Scenarios Breakdown
✅ PC / UPC fixed fiber attenuator: Telecom transmission, fiber power test, instrument calibration, short-reach single mode links.
✅ APC fixed attenuator: FTTH PON, CATV RF over fiber, analog optical signal, links sensitive to back reflection.
Critical Risk: Never Cross-Connect APC and PC
Inserting APC male into PC adapter will create air gap, bring extra insertion loss and unstable return loss, even cause intermittent link drop. This is one of the top field failure reasons for fiber fixed attenuator.
Matching with OAT-HF Attenuator Ordering Guide
OAT-HF ordering format: OAT-HF-Wavelength-Connector-Attenuation
Example: OAT-HF-1550-LC-APC-10dB, OAT-HF-1310-SC-PC-5dB
We support custom dB values for bulk order as fiber optic attenuator manufacturer for Europe.
Quick Selection Table
Telecom transmission link → PC/UPC
CATV / PON FTTH → APC
Fiber test equipment calibration → PC/UPC
High-speed coherent link requiring strict reflection control → APC high RL attenuator
Final Tips
High return loss ≥50dB is the core index of OAT-HF series.
Even with APC polish, low-quality attenuator cannot guarantee stable RL under wide temperature -40~+85℃.
Always confirm return loss specification before bulk procurement.