This part of IEC 61290 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 narrowband source, the effect can be related to
a differential group delay (DGD) between pairs of orthogonally polarized principal states
of polarization (PSP). Other information about PMD may be found in IEC 61282-9 in general
and in IEC 61292-5 on OAs in particular.
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.