Choose fiber for FTTH and FTTx by describing the access route and cable requirements before selecting a grade. The listed G.657.A1, A2 and B3 products provide different reference bend-test conditions and coating specifications to review. Start with the optical loss budget, operating wavelengths, equipment and joining requirements, then identify the physical constraints at distribution points and indoor routes. Keep bare-fiber macrobend tests separate from finished-cable installation limits. A tighter published test radius does not automatically make a grade necessary or qualify the completed cable. Use the product references to build a shortlist, confirm the offered specification and coating with the supplier, and include the required reel lengths and documentation in the RFQ.
Start with the installation
For FTTH optical fiber selection, map the access route, including building entry, closures, distribution cabinets and indoor sections. Record the cable construction and applicable installation instructions. The FTTH label alone does not resolve route geometry, handling or fiber acceptance requirements.
For an existing network, identify the installed fiber and interfaces. Explain whether the request is for a new cable design, replacement material or an extension so that joining and qualification questions can be reviewed in context.
Compare the source conditions
The A1 datasheet used here provides a defined 15 mm radius test. The A2 and B3 references include tighter-radius arrangements under their stated conditions. Review radius, turns, wavelength and loss together, rather than selecting by the smallest radius or lowest dB number alone.
Ask which condition the project requires and whether the actual offered product meets it. If the reference table does not answer that question, request clarification instead of extrapolating a new value.
Confirm coating and qualification requirements
Standard and reduced coating options should be reviewed against the intended cable design and production process. Confirm the exact diameter and tolerance, along with mode field and cladding specifications. Different source documents can contain different values, which is why each product page identifies its reference.
State any requirement for joining to existing fiber or meeting an internal qualification process. A general description of application suitability does not replace the agreed acceptance criteria.
Prepare a project-specific inquiry
Include the preferred grade, coating, total fiber-km, desired reel length, destination and required records. Attach or identify the governing specification and list acceptable alternatives separately. The quality and procurement guides help turn the shortlist into a request that can be technically reviewed.
What to confirm
- Access route and cable construction
- Operating wavelengths and loss budget
- Relevant bend-test arrangement
- Geometry, coating and joining requirements
- Reel allocation and batch documents
Frequently asked questions
Should every indoor route use B3?
Choose against the actual optical and finished-cable requirements. A more demanding reference bend test does not mean that every route requires that grade.
Does a fiber bend test define the cable installation radius?
No. Obtain the finished cable installation and handling instructions separately.
What should I send if I have not selected a grade?
Send the application, route constraints, wavelengths, equipment and required cable construction so the relevant specifications can be discussed.
Sources & reference context
This guide is published by OpticFiberHub and summarizes the supplier literature identified below with editorial purchasing guidance. Product values describe the source grade, not a measured result or a conformity guarantee for a new order.
- G.657.A1 reference specifications — BendCom G.657.A1 Bending Insensitive Single-mode Optical Fiber datasheet, pages 1–2.
- G.657.A2 reference specifications — Jiangsu Nanfang Optical Fiber Product Manual, pages 7–8.
- G.657.B3 reference specifications — Jiangsu Nanfang Optical Fiber Product Manual, pages 9–10.
Quality & technical resources explains source selection, translated documents and the limits of historical batch records. Request the current specification and applicable records for the actual offered material.
Further terminology reference: The Fiber Optic Association: optical fiber fundamentals.
Single-mode standard references: ITU-T G.652 and ITU-T G.657. Supplier reference values above must not be mistaken for a reproduction of every requirement in those Recommendations.
