This International Standard applies to all commercially available optical amplifiers (OAs), including optical fibre amplifiers (OFAs) using active fibres, semiconductor optical amplifiers (SOAs), and planar waveguide optical amplifiers (PWOAs). Polarization-mode dispersion (PMD) causes an optical pulse to spread in the time domain. This dispersion could impair the performance of a telecommunications system. The effect can be related to differential group velocity and corresponding arrival times of different polarization components of the signal. For a narrow-band source, the effect can be related to a differential group delay (DGD) between pairs of orthogonally polarized principal states of polarization (PSP). Other general information about PMD in OAs is reported in IEC 61292-5. This test method describes a procedure for measuring the PMD of OAs. The measurement result is obtained from the measurement of the normalized Stokes parameters at two closely spaced wavelengths. The test method described herein requires a polarized signal at the input of the polarimeter with a degree of polarization (DOP) of at least 25 %. Although the test source is highly polarized, the DOP at the output of the OA is reduced by amplified spontaneous emission (ASE). Annex A analyses the impact of ASE on the DOP. In order to assure an accurate measurement, the DOP is measured as part of the measurement procedure. The method described herein has been shown to be immune to polarization-dependent gain (PDG) and polarization dependent loss (PDL) up to approximately 1 dB. Although the Jones matrix eigenanalysis (JME) test method is in principle also applicable to unpumped (that is, unpowered) OAs, the JME technique in this standard applies to pumped (that is, powered) OAs only.