IEC 61300-3-53:2015

Overview

IEC 61300-3-53:2015 defines a standardized Encircled Angular Flux (EAF) measurement method for step index multimode waveguide light sources (including optical fibres and channel waveguides, but excluding slab waveguides). EAF quantifies the fraction of total optical power radiating from a waveguide core within a given solid angle and is reported as a function of the numerical aperture (NA) full angle. The method uses two‑dimensional far‑field (FFP) data captured with a calibrated camera and converts those images mathematically into EAF values.

Key topics and technical requirements

• Scope and definitions: EAF, FFP, NA and related terms specific to step‑index multimode waveguides.
• Measurement approaches:
  • Method 1 - fθ lens imaging: uses an fθ lens to map angular distribution to image height; requires an FFP optical system, calibrated camera and analyser software.
  • Method 2 - Direct imaging: options include integrating sphere, single‑mode fibre scanning, or direct imaging devices to collect far‑field power distribution.
• Apparatus components: micro‑positioner, FFP optical system, camera/detector, computer with EAF analyser, calibration light source and alignment optics.
• Calibration and geometric correction: procedures for geometric calibration of the imaging system and conversion from image coordinates to polar/angular coordinates.
• Measurement workflow: far‑field image acquisition, background noise removal, centre determination (optical or mechanical), computation of encircled angular flux vs NA.
• Data and reporting: standard EAF charts and optional information available on request (e.g., raw far‑field data, calibration details).
• Safety and normative references: compliance with IEC 60825‑1 for laser safety and IEC 61300‑1 for general fibre test guidance.

Applications and users

IEC 61300-3-53 is practical for:

• Fiber and component manufacturers verifying light‑source angular distributions and launch conditions.
• Test laboratories and OEMs performing acceptance testing, quality control and compliance checks.
• Network integrators and system designers modeling modal coupling, link budgets, and connector/assembly performance where accurate NA‑dependent source characterization is required.
• R&D teams studying mode excitation and far‑field behavior in multimode systems.

Typical uses include source qualification, modal launch validation, connector and assembly evaluation, and supplying standard EAF data for system simulations.

Related standards

• IEC 61300-1 - Fibre optic interconnecting devices and passive components: General and guidance (basic test procedures)
• IEC 60825-1 - Safety of laser products: Equipment classification and requirements

Keywords: encircled angular flux (EAF), measurement step index multimode waveguide light sources, numerical aperture, far‑field pattern, fθ lens, multimode fibre testing.