This International Standard 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 International Standard is to establish uniform requirement for accurate and reliable measurements, by means of the electrical spectrum analyzer (ESA) method, of the noise figure, as defined in International Standard IEC 61291-1. The present test method is based on direct electrical noise measurement and it is directly related to its definition including all relevant noise contributions. Therefore this method can be used for all types of optical amplifiers, including SOA and Raman amplifiers which can have significant contributions besides amplified spontaneous emission, because it measures the total noise figure. For further details to applicability, see IEC 61290-3-2. A different test method based on the optical spectrum analyzer can be used, particularly for different noise parameters (such as the signal-spontaneous noise factor) but it is not included in the object of this document. NOTE 1 - All numerical values followed by (*) are suggested values for which the measurement is assured. Other values may be acceptable but should be verified. NOTE 2 - A measurement accuracy for the average noise factor of ±20 %(*), respectively ±1 dB, should be attainable with this method (see clause 6). NOTE 3 - General aspects of noise figure test methods are reported in International Standard IEC 61290-3.