How to Choose Optical Fiber for FTTH Cable Manufacturing

Separate bare fiber sourcing from finished FTTH cable manufacturing

In this guide, bare optical fiber means the glass fiber with its protective coating, supplied on a reel. It is not an uncoated glass strand, a jacketed drop cable or a terminated assembly. OpticFiberHub supports sourcing this fiber material; the cable maker defines the cable construction and qualifies the finished product.

Create a cable design brief before asking for a grade recommendation. Identify indoor or outdoor use, fiber count, buffering, reinforcement, jacket requirements, connections and installation conditions. Finished-cable tensile, crush, environmental and fire requirements cannot be established from a bare-fiber attenuation or bend-loss table.

Build a shortlist from the actual product range

Review G.657.A1 for access designs requiring its listed bend and coating specification. Its source table gives 245 ± 10 μm or 200 ± 10 μm coating. G.657.A2 lists 242 ± 7 μm or 200 ± 10 μm, while G.657.B3 lists 242 ± 7 μm. Confirm the selected option rather than treating every grade as a common nominal coating.

G.652.D is another candidate where the feeder or distribution cable specification calls for its optical characteristics. The listed standard limit at 1550 nm is ≤ 0.185 dB/km; ≤ 0.180 dB/km is a separate optional low-loss grade. Neither value qualifies the completed cable or establishes that a particular network segment must use this product.

Keep wavelength and bend-test conditions attached to the limit

The listed A1, A2 and B3 products each specify ≤ 0.210 dB/km at 1550 nm, but their macrobend requirements differ. A1 lists ≤ 0.25 dB at a 15 mm radius with ten turns; A2 lists ≤ 0.40 dB at a 7.5 mm radius with one turn; B3 lists ≤ 0.15 dB at a 5 mm radius with one turn. These three bend limits are all at 1550 nm.

Do not rank these dB numbers as though they came from the same test. Request the required common test condition if the project needs a direct comparison. Record the complete cable loss budget separately, including splices, connections, splitters and engineering margin where applicable.

Qualify coating and handling on the intended production process

Have the production team review coating diameter, tolerance, handling instructions and the proposed reel format against the line requirements. A smaller coating may change the design space, but it does not by itself prove process compatibility, improved yield or a qualified microcable construction.

Agree on a trial and acceptance plan before changing an established material. Define the optical checks before and after cable processing, the relevant environmental or mechanical tests for the completed cable, and the documents needed for approval. Any U.S. or European project compliance must be supported for the actual finished product and intended use.

Turn the engineering review into a material RFQ

Send the fiber model, selected coating, specification revision, total fiber-km, preferred continuous length per reel and delivery destination. State whether alternatives are allowed and which tests or documents are mandatory. Request the offered product sheet, reel list and applicable batch report rather than relying only on a website example.

Use the linked FTTH factory procurement guide to reconcile quantity and reel allocation, then review the three-grade comparison when bend requirements drive the shortlist. Keep unresolved design questions visible in the inquiry so the quotation can identify exceptions before production approval.

Frequently asked questions