Description
This capillary is sized around a specific fiber standard — 125 µm cladding diameter — which is why it’s a separate product from general precision round capillary. The bore ID is chosen to match the fiber with a defined clearance, and the entry geometry (straight vs. bell-mouth/tapered) is part of the spec, not an afterthought.
Bore Diameter
| Parameter | Specification |
|---|---|
| Standard fiber cladding | 125 µm — 9/125 µm singlemode and 62.5/125 µm multimode standard fiber types |
| Bore ID examples | 0.125 / 0.126 / 0.127 mm |
| Bore-to-fiber clearance | Set by ID choice — larger ID for easier insertion, tighter ID for less lateral play |
| Core/bore concentricity | <0.5 µm achievable on precision ferrule-grade capillary |
| Diameter tolerance — fiber ferrule grade | <±2.0 µm standard; <±1.0 µm precision; <±0.5 µm high-precision |
Bore Geometry
| Type | Use |
|---|---|
| Straight bore | Direct fiber insertion, fixed clearance along the full length |
| Bell-mouth / tapered entry | Wider opening at the entry face, narrowing to the fiber-diameter bore — eases fiber insertion and reduces damage during assembly |
| Etched taper — dual-core spacing capillary | ID accuracy within ±0.001 mm, produced by an etching process for consistent taper geometry |
Application
- Fiber pigtail, collimator, CWDM/CCWDM/DWDM assembly
- Fiber fusion cone construction
- Optical fiber sleeve / packaging for fiber-optic devices
Material
High-purity fused quartz; refractive index and thermal expansion matched closely enough to standard optical fiber that fusion splicing and UV-adhesive bonding both perform reliably.
FAQ
Which bore ID should I choose — 0.125, 0.126, or 0.127mm?
It depends on your fiber outer diameter tolerance and how much clearance you want for insertion vs. positional precision. Tighter ID (0.125mm) minimizes lateral play; looser ID (0.127mm) eases insertion. Specify your fiber’s actual OD tolerance and we’ll confirm the right match.
What’s a bell-mouth entry and do I need one?
It’s a funnel-shaped widening at the capillary entrance that narrows down to the fiber bore — makes fiber insertion easier and reduces the risk of fiber damage during assembly. Recommended for any manual or semi-automated fiber insertion process.
Can concentricity be held tight enough for single-mode fiber alignment?
Yes — <0.5 µm core/bore concentricity is achievable on precision-grade capillary, suitable for single-mode fiber alignment tolerances.