Patent ID: 6429962
Filing Date: 2002-08-06
Classification: G02F,H01S,H04B

Abstract:
An optical equalizer comprising:an initial polarizer converting an input beam to a predetermined polarization; and a plurality of sinusoidal filters receiving the polarized beam in series providing attenuation as a sinusoidal function of beam wavelength, wherein each of said sinusoidal filters comprises: (a) a first liquid crystal cell adjustably rotating the polarization of the beam from the preceding polarizer as determined by a first control signal; (b) an optical element adjustably controlling the retardance of the beam from said first liquid crystal cell as a sinusoidal function of beam wavelength, wherein the degree of retardation is adjustably controllable by a second control signal, thereby allowing adjustment of the center frequency of the sinusoidal function; (c) a second liquid crystal cell adjustably rotating the polarization of the beam from said optical element as determined by a third control signal; and (d) a final polarizer passing that component of the beam from the second liquid crystal cell having a predetermined polarization, thereby providing amplitude control of the beam based on the polarization rotations provided by said first and second liquid crystal cells; wherein the combined sinusoidal attenuation functions of said sinusoidal filters produce a desired equalization curve as a function of beam wavelength.