Custom Fiber Optic Quartz Capillaries

Parameter	Typical Range
OD	0.3–3 mm
ID (bore)	125 µm fiber-alignment option: bore selected above the actual fiber OD by drawing; larger component/bundle reference bores 0.25–1.5 mm
Bore tolerance	125 µm fiber-alignment option: ±1–2 µm by agreed geometry; larger-bore reference: ±5–10 µm, subject to size and length review
Concentricity (bore-to-OD)	125 µm fiber-alignment option: ≤2 µm by agreed geometry and inspection; larger bores specified separately
Recommended bore clearance	Specify minimum/maximum diametral clearance from actual fiber OD, its tolerance, insertion length and adhesive requirement
Length	5–50 mm
End-face finish	Flat-cut, polished, or flared

Inquiry

Fiber optic quartz capillaries locate a fiber or fiber bundle within a controlled bore for alignment sleeves, optical feedthroughs and end-cap interfaces. Select the bore from the actual fiber diameter and assembly clearance, then define how that bore must align with the outside mounting surface.

Bore Clearance for 125 µm Fiber

State whether the fiber is bare, coated or stripped over the insertion length. A nominal 125 µm cladding diameter is not the finished bore specification: minimum diametral clearance is the minimum capillary ID minus the maximum actual fiber OD. Allow for fiber tolerance, adhesive space and insertion length; do not assume a nominal 125 µm bore provides a slip fit.

Concentricity vs. Bore Tolerance

Bore tolerance controls the size of the passage; bore-to-OD concentricity controls its position when the outside is used as the mounting datum. For the 125 µm fiber-alignment option, the listed ±1–2 µm ID and ≤2 µm concentricity requirements must be agreed for the complete OD and finished length. The larger-bore reference tolerance of ±5–10 µm applies to a separate component/bundle series, rather than to that alignment option.

Fiber Entry and End-Face Options

A chamfer or flared entry helps thread the fiber without changing the specified working bore. Identify the lead-in length, insertion direction and the end face used as the axial datum. Ground, optically polished and fire-polished ends serve different functions; specify the required face quality and keep the entry free of chips or deformation that could damage the fiber.

Fit Starts with the Fiber

Specify Bore Clearance Before OD and Length

Controlled Feature	What to Put on the Drawing
Fiber / Component OD	Nominal diameter and its toleranceThe capillary bore is selected from the actual mating component, not from a generic tube size
Finished Bore ID	Fiber OD plus the required insertion, adhesive or thermal-expansion clearance
ID Tolerance	125 µm fiber-alignment option: ±1–2 µm by agreed geometry. Larger component/bundle bores: reference ±5–10 µm, reviewed by ID, OD, finished length and inspection method.
Outer Diameter / Profile	Round OD or a drawing-specific outer datum for the holder
Concentricity	125 µm fiber-alignment option: ≤2 µm by agreed geometry and inspection; larger bores specified from the OD or functional outer datum
Taper	Maximum permitted ID change over the working length where fiber alignment depends on it
Finished Length	Cut length with the end-face datum identified
End Geometry	As-cut / ground square / polished / chamfered / flared entry

Bore Selection

Common IDs for Fiber and Component Alignment

Reference Bore ID	Typical Mating Element	Quote-Critical Detail
125 µm fiber-alignment option	Bare-fiber alignment, with finished bore selected above actual fiber OD	Actual element OD, insertion clearance and finished length
0.25 / 0.30 mm	Coated fiber, small optical element or sensor lead	Coating condition and whether adhesive space is required
0.50 / 0.80 mm	Fiber bundles, ferrules and compact feedthroughs	Bore centering and end-entry geometry
1.0 / 1.5 mm	Larger optical elements and protected transitions	OD fit, wall section and end-face finish

Interface Options

End Geometry That Protects the Fiber During Assembly

Precision Round BoreCentered channel for repeat fiber position inside a round OD

Flared Fiber EntryLead-in geometry reduces edge contact during fiber insertion

Chamfered EndsDefined entry chamfer for assembly without a sharp bore edge

Ground or Polished FacesFinished ends for optical interfaces, bonding and controlled axial length

Applications

Where Bore Position Matters More Than Tube Size

Fiber Alignment & SplicingCentered sleeves and transitions that hold fibers on a repeat optical axis

Ferrules & Optical FeedthroughsQuartz interfaces for bonding, packaging and passage through instrument housings

Photonic & Medical ProbesSmall rigid guides where fiber clearance, entry geometry and finished length control assembly

Need a capillary matched to a fiber?Send fiber OD and tolerance, target bore clearance, capillary OD, finished length and end-face drawing.

Open the Capillary Configurator

Engineering Data

Grade-Qualified Material Purity

Electric-fused / flame-fused quartz: SiO₂ ≥99.99%; synthetic JGS1-grade fused silica: ≥99.999%. Grade and lot certificate govern supplied material.

Engineering Data

Related Quartz Parts for VAD, OVD and Fiber Drawing

Optical-fiber manufacturing components include quartz seed and support rods for VAD / OVD deposition, tail tubes, VAD connectors and sintering rings, isolation covers, draw-furnace sealing sleeves, quartz gaskets and pressure-ring tail seals. Support rods · Sealing sleeves · Sintering and pressure rings. These are process fixtures specified by drawing, separate from the precision capillary bore series.