Calibration of the polarisation mode dispersion (PMD) of both low mode coupled and high mode coupled devices and optical fibres. Calibration at 1310 nm and 1550 nm. NPL calibration artefacts are also available.

Polarisation mode dispersion is a measure of the dependence of the transit time of light travelling down a fibre on the polarisation state of the light. It depends on the fibre itself and on external factors such as stress, bends and temperature. In fibres where the modes are highly coupled, for example long spans, the PMD is a statistical effect since it depends on the details of the birefringence and mode coupling along the entire fibre length. Due to this statistical nature, there may be limits to the accuracy which this parameter may be measured and work is in progress to examine these.

Measurement facilities for PMD have been developed based on the Polarimeter (Stokes Vector) measurement method. In this technique, polarised light from a tunable laser is launched into the fibre or component under test and the output polarisation state is measured as a function of wavelength from which the PMD is calculated. PMDs in the range 5 fs to 10 ps can be measured. In low mode coupled fibre, for example HiBi fibre, where the statistical limit is not significant, accuracies of 2 % (PMD > 300 fs) are achievable.

Calibration artefacts are available, as is more information about PMD measurements ( PDF 212 KB).

A copy of a typical Calibration Certificate is available to download.

Contact

Customer Service tel: +44 20 8943 8637
E-mail: fibreoptics_enquiries@npl.co.uk