This part of IEC 61290 applies to optical amplifiers (OAs) using active fibres presently commercially available containing rare-earth dopants. The object of this standard is to establish uniform requirements for accurate and reliable measurements, by means of the filtered optical power meter test method, of the following OA parameters, as defined in IEC 61291-1: a) out-of-band insertion loss; b) out-of-band reverse insertion loss. NOTE 1 The out-of-band insertion loss of an OA is highly dependent on the amplifier configuration and the out-ofband wavelength. NOTE 2 All numerical values followed by (‡) are suggested values.