Here’s a production-ready Polishing Recipe for Single-Mode MPO / MTP® ferrules, specifically tailored for MTP-16 / MTP-24 / MTP-32 connectors. This recipe is based on verified industry practice and provides step-by-step abrasives, grit sizes, and target Ra for optical performance.
MTP® / MPO Single-Mode Ferrule Polishing Recipe
Standards: IEC 61755 / Telcordia GR-326
Fiber Type: Single-Mode
Connector Types: MTP-16, MTP-24, MTP-32 and More (UPC & APC)

1️⃣ Polishing Materials & Consumables
| Item | Specification | Notes |
|---|
| Abrasive Films | Diamond, Silicon Carbide (SiC), Aluminum Oxide (Al₂O₃), Silicon Dioxide (SiO₂), Cerium Oxide (CeO₂) | PSA-backed or sheet format for platen |
| Polishing Pads | Glass or ceramic | Flat, clean, and hard for consistent polishing |
| Lubricant | DI Water or DI Water + slurry | Keeps debris from scratching ferrule surface |
| Cleaning | Lint-free wipes, IPA | Between each polishing step |
| Inspection Tools | Microscope, interferometer, IL/RL tester | Visual and optical verification |
2️⃣ Multi-Stage Polishing Recipe
Step 1 – Epoxy Removal & Surface Flattening
| Abrasive | Grit / Micron | Pad | Target Ra (µm) | Duration | Notes |
|---|
| SiC or Diamond | 30–60 µm | Glass | 0.3–0.5 | 30–60 sec | Remove epoxy flash and high spots |
| Water lubrication | – | – | – | Continuous | Ensure debris is flushed |
Step 2 – Geometry Shaping & Fiber Height Control
| Abrasive | Grit / Micron | Pad | Target Ra (µm) | Duration | Notes |
|---|
| SiC or Diamond | 9–3 µm | Glass | 0.1–0.2 | 30–60 sec | Establish end-face radius, uniform fiber height |
| Aluminum Oxide | 3–1 µm | Glass | 0.05–0.08 | 30–60 sec | Smooth intermediate scratches |
Step 3 – Fine Pre-Polish
| Abrasive | Grit / Micron | Pad | Target Ra (µm) | Duration | Notes |
|---|
| SiC / Diamond / Al₂O₃ | 1 µm | Glass | 0.03–0.05 | 30–60 sec | Minimize scratches, prep for final polish |
Step 4 – Final Optical Polish
| Abrasive / Slurry | Micron | Pad | Target Ra (µm) | Duration | Notes |
|---|
| SiO₂ or CeO₂ | 0.05–0.5 µm | Glass Pad | 0.01–0.03 | 30–60 sec | Mirror finish, low IL, high RL |
| Wet polishing | Continuous | – | – | – | Essential for smooth finish |
3️⃣ Post-Polish Inspection
Microscope inspection: Ensure no scratches, pits, or fiber pull-out.
Geometry measurement: Apex offset, end-face radius, fiber height uniformity.
Optical testing:
4️⃣ Notes & Best Practices
Always clean films, pads, and ferrules between steps.
Use light, even pressure; avoid excessive force.
Replace films when cutting efficiency decreases.
APC connectors require an 8° angled final polish.
Document Ra, fiber height, IL, and RL for traceability.