Overview
EN ISO 14881:2021 - Integrated optics - Interfaces - Parameters relevant to coupling properties - is a CEN-adopted international standard that defines the vocabulary and key parameters for coupling lightwaves into and out of integrated optical chips (IOC) and photonic integrated circuits (PIC). The standard concentrates on butt coupling via waveguide endfaces, providing a unified set of definitions that form the basis for specifying elements to be coupled (e.g., optical fibres, fibre arrays, chips) with respect to coupling properties.
Key topics and technical requirements
The document standardizes terms and parameters relevant to optical coupling. Principal topics include:
- Coupling geometry
- Chip geometry and waveguide geometry (endface locations, chip surfaces, facets)
- Beam axis and spot size descriptions for guided lightwaves
- Coupling performance metrics
- Coupling efficiency (η) - ratio of coupled power to emitted power
- Coupling loss (αc) - logarithmic loss expressed in dB (caused by misalignment, mode mismatch, reflections)
- Interface and endface properties
- Endface quality, anti-reflective coatings, Fresnel loss
- Index matching techniques (e.g., λ/4 layer) to reduce reflections
- Fibre and array considerations
- Fibre tolerances, pitch (centre-to-centre spacing), fibre array coupling and fibre array coupling deviation
- Array block and fixed alignment structures for precise mechanical alignment
- Normative references and harmonization
EN ISO 14881:2021 focuses on definitions and parameterization rather than prescribing measurement procedures; it provides the vocabulary and parameters used when specifying and testing coupling interfaces.
Practical applications
This standard is practical for anyone specifying, designing or testing optical interfaces where efficient fibre-to-chip or chip-to-chip coupling is required. Typical uses include:
- Specifying fibre-to-PIC interfaces and acceptance criteria for coupling loss and efficiency
- Design and tolerancing of waveguide endfaces, chip facets and anti-reflective coatings
- Engineering of fibre arrays, V-groove array blocks and fixed alignment structures
- Test-laboratory reporting and supplier–customer contracts that reference unified coupling parameters
Who should use this standard
- Photonics and integrated optics engineers
- Optical component and PIC manufacturers
- Fibre and connector designers
- System integrators and test laboratories
- Standards and procurement teams specifying optical interface requirements
Related standards
Using EN ISO 14881:2021 ensures consistent terminology and parameter definitions across design, production and testing of integrated-optic coupling interfaces, improving interoperability and clarity in specifications.