IEC 62614-1:2020

Overview

IEC 62614-1:2020 - Fibre optics: Multimode launch conditions (Part 1) specifies launch condition requirements for measuring multimode attenuation in passive components and installed cable plants. It defines how test sources and launch cords must present light at the fibre interface using a controlled encircled flux (EF) to achieve consistent, repeatable attenuation measurements for multimode fibres (A1‑OMx: 50 µm/125 µm and A1‑OM1: 62.5 µm/125 µm) at 850 nm and 1300 nm. The standard harmonizes factory and field testing practices and updates earlier editions with revised uncertainty and reference alignments.

Key topics and technical requirements

• Encircled Flux (EF) specification: EF is defined from the near-field power distribution and is the central metric for launch condition control. EF templates in the standard set target EF values at specific radial control points for each fibre/wavelength combination.
• Launch at the reference-grade launch cord output: Requirements are described at the output of a reference grade launch cord; test equipment manufacturers should verify EF compliance per IEC 61280-1-4.
• Fibre categories and wavelengths: Targets are provided for 50 µm (OM2–OM5) and 62.5 µm (OM1) multimode fibres at 850 nm and 1300 nm. EF target tables and illustrative templates are included to guide measurement setup.
• Uncertainty and harmonization: The edition increases the uncertainty attenuation variation coefficient (Y) for 50 µm at 1300 nm and aligns measurement criteria with IEC 61280-4-1:2019 and IEC 60793-2-10:2019 to reduce wavelength bias.
• Practical limitations and expectations: The document describes expected tolerances, practical constraints (core diameter tolerances, NA, concentricity), and guidance to improve reproducibility across different test instruments.

Applications and users

• Who uses it:
  • Test equipment and launch cord manufacturers (to qualify EF performance)
  • Fibre optic installers and field technicians (for consistent attenuation testing)
  • Factory QA labs (to correlate production and field attenuation measurements)
  • Network designers and integrators validating multimode cable plants
• Practical benefits:
  • Ensures repeatable multimode attenuation results across instruments
  • Reduces measurement differences caused by modal distributions and differential mode attenuation (DMA)
  • Supports compliance testing of passive components, patchcords and installed links at 850 nm and 1300 nm

Related standards

• IEC 61280-1-4 - Light source encircled flux measurement method (normative reference)
• IEC 61280-4-1:2019 - Harmonized test procedures (referenced changes)
• IEC 60793-2-10:2019 - Multimode fibre category definitions (OM1–OM5)
• IEC 61755-6-2 - Reference-grade terminations (connector tolerances)

Keywords: IEC 62614-1:2020, multimode launch conditions, encircled flux, multimode attenuation measurement, A1‑OMx, 50 µm/125 µm, 62.5 µm/125 µm, 850 nm, 1300 nm.