IEC 61290-3:2008 applies to all commercially available optical amplifiers (OAs), including OAs using optically pumped fibres (OFAs based on either rare-earth doped fibres or on the Raman effect), semiconductor optical amplifiers (SOAs) and planar waveguide optical amplifiers (PWOAs). The object of this standard is to provide the general background for OA noise figure parameters measurements and to indicate those IEC standard test methods for accurate and reliable measurements of OA parameters, as defined in IEC 61291-1. This edition includes updates to specifically address additional types of optical amplifiers and to highlight that the IEC 61290-3 series pertains to single-channel amplifiers. References have been added to the documents pertaining to multichannel amplifiers.