Overview
IEC 60793-1-61:2017 defines uniform measurement methods and test procedures for polarization crosstalk in polarization‑maintaining (PM) optical fibres. The standard describes two complementary measurement techniques - Method A (power ratio) and Method B (in‑line polarimetric/Poincaré‑sphere analysis) - and specifies test conditions, apparatus recommendations and reporting conventions. Method A yields an averaged crosstalk value and is the Reference Test Method (RTM) used in product specifications, while Method B provides a worst‑case accumulated crosstalk assessment.
Key topics and requirements
- Scope: Measurement of polarization crosstalk for PM fibres, connectors and joined assemblies.
- Two methods
- Method A - Power ratio method: Measure minimum and maximum output power at a specified wavelength by rotating polarizer and analyser; compute crosstalk as a power ratio and average two orthogonal input orientations. This is the RTM referenced in IEC 60793-2-70.
- Method B - In‑line polarimetric method: Polarimetric monitoring and Poincaré‑sphere analysis to find the worst‑case accumulated crosstalk along the fibre (sensitive to temperature and mechanical stress).
- Test apparatus: Light source, depolarizer or polarization controller, polarizer, analyser, detector and low‑stress fibre mounting (e.g., V‑groove). Minimize cladding modes and avoid bending that alters crosstalk.
- Light source: Broadband source recommended (LED or SLD) with ≥20 nm FWHM or appropriately short coherence length; avoid high power that induces non‑linear effects (typical safe limit ~10 mW).
- Polarizer/analyser: Polarization extinction ratio (PER) should be at least 10 dB higher than expected maximum crosstalk.
- Detector: Linear response within ±5% over measurement range and polarization‑independent response.
- Test conditions: Use standard environmental conditions per IEC 60068‑1 unless otherwise justified.
Applications and users
IEC 60793-1-61 is essential for:
- Fibre manufacturers and test labs establishing PM fibre performance and product compliance.
- Component and system designers validating polarization handling in sensors, interferometric links, coherent communications and fibre‑optic gyroscopes.
- Quality assurance, acceptance testing and dispute resolution where a standardized RTM (Method A) is required.
The standard helps ensure repeatable, comparable polarization crosstalk data for product specifications, procurement and system integration.
Related standards
- IEC 60793-1-1 - Measurement methods: general guidance.
- IEC 60793-2-70 - Product specifications for polarization‑maintaining fibres (references Method A).
- IEC 60068-1 - Environmental test conditions and guidance.
Keywords: IEC 60793-1-61, polarization crosstalk, PM fibres, power ratio method, in‑line polarimetric, Poincaré sphere, optical fibres, measurement methods, test procedures.
Open preview (PDF)Optical fibres - Part 1-61: Measurement methods and test procedures - Polarization crosstalk
