Patent ID: 8605247

Claim:
A wavelength selective switch comprising: a wavelength dispersive element for separating an input beam into its wavelength components; a liquid crystal switch for directing each of the wavelength components to a primary optical path and a residual optical path, wherein the liquid crystal switch includes a beam polarization unit that is positioned in an optical path of one of the wavelength components and in the primary optical path and the residual optical path of said one of the wavelength components, the beam polarization unit comprising an array of liquid crystal (LC) pixels, one of which positioned in an optical path of each of the wavelength components and the primary optical path and the residual optical path of said each of the wavelength components; a beam steering unit for directing each of the wavelength components to the primary optical path and the residual optical path; a beam reflecting element positioned in the primary optical path and the residual optical path to cause a light beam traveling along the primary optical path to reflect off the beam reflecting element and pass through the beam polarization unit and a light beam traveling along the residual optical path to reflect off the beam reflecting element and pass through the beam polarization unit; and a quarter wave plate positioned between the beam steering unit and the beam reflecting element.