IEC 61300-3-47:2014

Overview

IEC 61300-3-47:2014 specifies an interferometric procedure to examine and measure the end face geometry of PC/APC spherically polished ferrules or connectors. It defines how to record and compute critical geometry parameters (radius of curvature, apex offset, fibre height, end-face angle) using an optical interferometer combined with a microscope and camera. Within this standard the terms “ferrule” and “connector” are used interchangeably.

Key topics and technical requirements

• Measured parameters
  • Radius of curvature (domed portion of the end face)
  • Apex offset (distance between ferrule axis and dome vertex)
  • Fibre height (average distance between the fibre end and a fitted virtual spherical surface)
  • End-face angle, tilt and key angle for angled/flat polished ferrules
• Measurement system
  • Interferometer (e.g., Michelson-type) producing interference fringes
  • Ferrule/connector holder with axial alignment capability
  • Microscope + camera with a minimum field of view of 250 µm; software for fringe analysis
• Calibration and performance requirements
  • XY calibration (radius of curvature) uncertainty: better than ±0.1 mm for radii 5–30 mm
  • Z calibration (fibre height) uncertainty: better than ±10 nm
  • Apex offset repeatability: maximum difference < 5 µm when rotated 180° (non-angled ferrules)
  • Tilt and key angle measurement uncertainty: typically better than ±0.03° (tilt) and ±0.1° (key) for flat polished ferrules
• Normative/Informative annexes
  • Annex A: interferometer calibration procedures
  • Annex B: measurement procedure for angled convex-polished ferrules
  • Annex C: formulas for computing ferrule end-face geometry

Applications and who uses this standard

• Manufacturers of fibre optic connectors and ferrules - for production QC and process control
• Test laboratories and quality assurance teams - for acceptance testing and certification
• Design and R&D engineers - to validate polishing processes and connector performance
• Field service and failure analysis - to investigate connector end-face defects that affect optical performance Practical uses include ensuring physical contact quality, minimizing insertion loss/return loss variations, and verifying connector interchangeability.

Related standards

• This document is part of the IEC 61300 series (Fibre optic interconnecting devices and passive components – Basic test and measurement procedures). IEC 61300-3-47 consolidates and replaces several earlier parts (e.g., 3-15, 3-16, 3-17, 3-23).

Keywords: end face geometry, spherically polished ferrule or connector, interferometry, radius of curvature, apex offset, fibre height.