This part of IEC 61300 presents a number of alternative methods for measuring the polarization mode dispersion (PMD) of a passive fibre optic device under test (DUT). These methods typically measure PMD using either a frequency domain or time domain approach. In the frequency domain, the polarization properties of the DUT are analysed. In the time domain approach, the pulse delay or broadening is observed. This procedure will cover measurements of both broadband, and narrowband dense wavelength division multiplexing (DWDM) passive fibre optic devices. Differences between measurement practices for these varied classes of passive fibre optic devices will be noted in the text. This procedure can be applied to laboratory, factory and field measurements of PMD in passive fibre optic devices. Limitation of the application of some methods will be noted in the text when necessary. This procedure can be applied to a transmissive or reflective DUT. In the latter case, the DUT connection is via a coupler or circulator, which should have a known very low PMD value.