Optical circuits for tunable second order PMD compensation and tunable dispersion compensation

摘要

A method and an apparatus is provided for introducing tunable second order polarization mode dispersion compensation to an optical signal without introducing any first order polarization mode dispersion into the optical signal. A method and an apparatus is also provided for tunable chromatic dispersion compensation by rotating the polarization state of an input signal to match the chromatic like second order PMD compensation provided by the present invention. In one configuration, birefringent elements are arranged into at least two stages, each stage having at least two birefringent elements, each birefringent element of one stage oriented orthogonal to a corresponding birefringent element of a corresponding stage. In another configuration, the polarization of optical signals emerging from each birefringent element are rotated to create effective orthogonal orientations between corresponding birefringent elements of corresponding stages.