IEC 61290-1-3:2015 applies to all commercially available optical amplifiers (OA) and optically amplified subsystems. It applies to OA using optically pumped fibres (OFA based on either rare-earth doped fibres or on the Raman effect), semiconductors (SOA), and waveguides (POWA). The object of this part of IEC 61290-1 is to establish uniform requirements for accurate and reliable measurements, by means of the optical power meter test method, of the following OA parameters, as defined in IEC 61291-1: - nominal output signal power; - gain; - polarization-dependent gain; - maximum output signal power; - maximum total output power. All numerical values followed by (‡) are suggested values for which the measurement is assured. Other values may be acceptable but should be verified. This part of IEC 61290-1 applies to single-channel amplifiers. For multichannel amplifiers, the IEC 61290-10 series applies. This third edition cancels and replaces the second edition published in 2005. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - Detail description of most parameters has been described in IEC 61290-1 and removed from this part; - Description of maximum output signal power and maximum total output power are added. Keywords: optical amplifiers (OA), single-channel amplifiers, optical power meter test method This publication is to be read in conjunction with IEC 61290-1:2014.