Inspect the optical spot on the end face of the fiber optic patch cord

Inspect the fiber optic end face using a microscope or automated scope, focusing on core, cladding, and ferrule zones to detect scratches, debris, or cracks according to IEC 61300-3-35 standards.

Key Steps for End Face Inspection

1. Prepare the Fiber and Tools

• Use a fiber microscope or automated inspection scope with 200x–400x magnification for single-mode fibers to clearly see the core and cladding defects .
• Ensure the fiber is disconnected from live equipment to prevent laser exposure .
• Handle the patch cord with gloves and avoid touching the end face to prevent contamination . 2. Identify Inspection Zones IEC 61300-3-35 defines four concentric zones on the fiber end face:
• Zone A (Core): The most critical area where light enters or exits. Must be free of scratches, pits, or debris .
• Zone B (Cladding): Surrounds the core; minor scratches (<1 µm) may be tolerated but still affect performance .
• Zone C (Adhesive/Epoxy): Defects are less critical unless they extend into the fiber region .
• Zone D (Ferrule Contact Surface): Usually less sensitive; defects here are tolerated within limits . 3. Inspect for Defects
• Look for scratches, cracks, chips, or debris on the end face .
• Scratches in Zone A can scatter light and cause significant signal loss .
• Cracks or edge chips may grow under stress and impair mating with other connectors .
• Fixed contamination like cured epoxy or embedded particles can partially block light and increase insertion loss . 4. Cleaning and Reinspection
• If contamination is detected, clean the end face using fiber cleaning wipes or alcohol-based solutions.
• Reinspect after cleaning to ensure the end face meets the pass criteria .
• Always inspect both ends of the patch cord, as defects on either side can degrade performance . 5. Pass/Fail Criteria
• Follow IEC 61300-3-35:2015 for quantitative assessment of scratches, pits, and debris .
• Single-mode fibers: no scratches or defects in the core zone.
• Multimode fibers: scratches ≤3 µm and up to four defects ≤5 µm may be acceptable . 6. Documentation and Consistency
• Automated scopes can provide pass/fail results, logs, and serial number tracking for quality control .
• Manual inspection is acceptable if operators are trained and follow consistent internal criteria aligned with IEC standards . By following these steps, you ensure that the fiber optic patch cord end face is clean, undamaged, and capable of maintaining optimal optical performance. Proper inspection prevents signal loss, reflection, and potential damage to network equipment.