Liquid crystal optical device configured to reduce polarization dependent loss and polarization mode dispersion

An optical device comprising:

• a birefringent displacer for dividing an input beam into a first component and a second component, the birefringent displacer including a first birefringent crystal and a second birefringent crystal, the first and second birefringent crystals having different thicknesses;
• a liquid crystal structure (LC) for conditioning the polarization state of incident light and disposed in optical paths of the first and second components;
• and
• a half-wave plate disposed in the optical path of the first component between the birefringent displacer and the LC structure.

A wavelength selective switch comprising:

• a wavelength dispersive element for separating an input beam into its wavelength components;
• a birefringent displacer disposed in optical paths of the wavelength components, the birefringent displacer including a first birefringent crystal and a second birefringent crystal, the first and second birefringent crystals having different thicknesses;
• a liquid crystal structure (LC) for conditioning the polarization state of incident light and disposed in optical paths of the wavelength components;
• and
• a half-wave plate disposed between the birefringent displacer and the LC structure.

A method for reducing the polarization dependent loss (PDL) of an input beam that passes through a liquid crystal optical device having a birefringent displacer, said method comprising:

• measuring the PDL of the input beam;
• rotating the birefringent displacer;
• and
• measuring the PDL of the input beam after rotation of the birefringent displacer.