IEC 61290-1-1:2015(E) applies to all commercially available optical amplifiers (OAs) and optically amplified modules. It applies to OAs using optically pumped fibres (OFAs based on either rare-earth doped fibres or on the Raman effect), semiconductor OAs (SOAs) and planar optical waveguide amplifiers (POWAs). The object of this standard is to establish uniform requirements for accurate and reliable measurements, by means of the optical spectrum analyzer 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. The object of this standard is specifically directed to single-channel amplifiers. For multichannel amplifiers, one should refer to the IEC 61290-10 series. This third edition cancels and replaces the second edition published in 2006 and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: updates on the characteristics of measurement apparatus and revised list of addressed optical amplifier parameters. Keywords: optical amplifiers, optical spectrum analyzer test, single-channel amplifiers