IEC 60793-1-47:2017

Overview - IEC 60793-1-47:2017 (Macrobending loss of optical fibres)

IEC 60793-1-47:2017 specifies standardized measurement methods and test procedures for macrobending loss of optical fibres. The standard covers single‑mode fibres (class B) and several multimode categories (A1, A3, A4) at defined wavelengths:

• Class B single‑mode: 1550 nm or 1625 nm
• Category A1 multimode: 850 nm or 1300 nm
• Categories A3/A4 multimode: 650 nm, 850 nm or 1300 nm

Its purpose is to provide uniform requirements to support inspection, commercial acceptance, and quality control of fibres and cables by quantifying macrobending sensitivity.

Key topics and technical requirements

• Two normative measurement methods
  • Method A – Fibre winding: intended for class B single‑mode and A1 multimode fibres; uses mandrels or winding supports with defined curvature radii and number of turns.
  • Method B – Quarter‑circle bends: intended for A3 and A4 multimode fibres; uses quarter‑circle supports or grooves to produce discrete bends.
• Measurement techniques
  • Transmitted power monitoring technique (Annex A, normative) - continuous power monitoring against reference.
  • Cut‑back technique (Annex B, normative) - standard attenuation measurement by comparing long and short specimen lengths.
• Launch and source requirements
  • Annex C defines optical source and encircled flux requirements for A1 multimode measurements to ensure reproducible modal excitation.
• Definitions and apparatus
  • Clear definition of curvature radius (radius of circular support) and apparatus details (input launch, detectors, guides).
• Informative guidance
  • Annex D discusses small‑radius phenomena (mode interference, polarization, high‑power effects).
  • Annex E provides a parallel‑plate (2‑point) macrobend loss approximation to estimate bend loss across wavelengths.
• Important note: Methods A and B may produce different loss results on the same fibre because bend radius, bend length and deployment scenarios differ.

Practical applications and users

This standard is essential for:

• Fibre and cable manufacturers - product characterization and acceptance testing.
• Test laboratories and QA teams - repeatable macrobend loss measurements for specs and contracts.
• Network planners and installers - understanding bending sensitivity for cabling design and routing.
• Procurement and compliance - verifying supplier claims and confirming commercial acceptance criteria.

Use IEC 60793-1-47:2017 when defining test plans for macrobending loss, comparing fibres for bend‑sensitive applications, or documenting compliance in datasheets.

Related standards

• IEC 60793 series (Optical fibres) - see IEC 60793-1-1:2017 for related general requirements and terms.