This part of IEC 61290 applies to optical amplifiers (OAs) using active fibres and waveguides, containing rare-earth dopants, currently commercially available. The object of this standard is to establish uniform requirements for accurate and reliable measurements of the signal-spontaneous noise figure as defined in IEC 61291-1. The test method independently detects amplified signal power and amplified spontaneous emission (ASE) power by launching optical pulses into the OA under test and synchronously detecting "on" and "off" levels of the output pulses by using an optical sampling switch and an optical spectrum analyzer (OSA). Such measurement is possible because the gain response of the rare-earth doped OA is relatively slow, particularly in Er-doped OAs. However, since the OA gain dynamics vary with amplifier types, operating conditions and control schemes, the gain dynamics should be carefully considered when applying the present test method to various OA. The manufacturer of the OA should present data validating the required modulation frequency to limit the error to <1 dB. The measurements for obtaining this information are described in Annex C. The test method is described basically for multichannel applications, which includes single channel applications as a special case of multichannel (wavelength-division multiplexed) applications. NOTE All numerical values followed by (‡) are currently under study.