IEC 61300-3-20:2001

Overview

IEC 61300-3-20:2001 is an international standard titled "Fibre optic interconnecting devices and passive components - Basic test and measurement procedures - Part 3-20: Examinations and measurements - Directivity of fibre optic branching devices" published by the International Electrotechnical Commission (IEC). This standard specifies a precise methodology for measuring the directivity of light between channels in multiport, non-wavelength-selective MxN fibre optic branching devices (BDs).

Directivity is defined as the fraction of optical power that unintentionally couples from one input path to another input port that should ideally remain isolated. The standard ensures reliable measurement of this critical parameter, which is essential for maintaining high performance and signal integrity in fibre optic networks.

Key Topics

• Purpose and Scope: Measurement of directivity in fibre optic branching devices used in passive optical networks.
• Directivity Definition: The ratio of unintended optical power transfer between isolated input ports, expressed in decibels (dB).
• Measurement Procedure:
  • Comparing optical power from a reference input connected to a light source and the power measured at an isolated input port.
  • Use of high dynamic range optical power meters and stable light sources.
• Measurement Challenges:
  • Suppression of ambient light interference.
  • Reduction of reflections at fibre end faces.
  • Control of light propagation in cladding modes.
  • Managing low-level optical signals with accurate detection.
  • Mitigating Rayleigh scattering effects in fibre pigtails.
• Equipment Requirements:
  • Optical source with appropriate wavelength characteristics and cladding mode suppression.
  • Temporary joint devices for stable, low-loss fibre alignment.
  • High-return-loss terminations to minimize reflection noise.
  • High precision detectors/power meters with zeroing capability.

Applications

IEC 61300-3-20:2001 provides practical test methods for designers, manufacturers, and testing labs involved in:

• Quality Assurance of Fibre Optic Branching Devices: Ensuring devices meet strict directivity requirements to prevent crosstalk and signal degradation in optical communication systems.
• Passive Optical Networks (PON): Supporting node performance verification where multiple fibre inputs and outputs converge.
• Telecommunications Equipment Validation: Reliable measurement procedures ensure compliance with industry standards for fibre optic components.
• Optical Component Research and Development: Facilitates benchmarking and improvement of new multiport fibre optic devices.
• Maintenance and Troubleshooting: Helps identify directivity related issues in installed fibre optic branching devices.

The use of this standard helps optimize network performance by minimizing unintended optical power leakage, supporting high data integrity and system stability.

Related Standards

• IEC 61300 Series: This standard is part 3-20 of the IEC 61300 series, which covers basic test and measurement procedures for fibre optic interconnecting devices and passive components.
• IEC 60793 and IEC 60794: Standards covering optical fibres and fibre cables, relevant for source and detector compatibility.
• IEC 61757 Series: Provides performance requirements and test methods for passive optical components, complementing directivity measurements.
• ISO/IEC Directives, Part 3: Standard formatting and drafting guidance followed for consistency across standards.

Keywords: IEC 61300-3-20, fibre optic branching devices, directivity measurement, fibre optic interconnecting devices, passive optical components, optical power measurement, fibre optic testing procedures, multiport fibre optics, optical network performance, IEC standards.