Polarization rotator

Such devices can be based on the Faraday effect, on birefringence, or on total internal reflection.

[1] A Faraday rotator consists of an optical material in a magnetic field.

When light propagates in the material, interaction with the magnetic field causes left- and right-handed circularly polarized waves to propagate with slightly different phase velocities.

In particular, the PSG and PSA made with magneto-optic (MO) switches have been successfully used to analyze polarization mode dispersion (PMD) and polarization dependent loss (PDL) with accuracies not obtainable with rotating waveplate methods, thanks to the binary nature of the MO switches.

Because they are based on total internal reflection, they are broadband—they work over a broad range of wavelengths.