IEC TR 63309:2025

IEC TR 63309: 2025, which is a Technical Report, provides an introduction of active fibres describing key characteristics and measurement methods. For the purpose of this document, an active fibre is a silica-based optical fibre doped in the core with rare-earth ions to allow optical gain, named rare-earth doped fibre. Other fibres enabling optical gain by means of different effects (e.g. Raman effect) are not included in the scope of this document.