A method and apparatus that includes a first waveguide segment that differentially changes the amplitude of the light relative to a first polarization orientation, a thickness of oriented liquid crystal or other birefringent material sufficient to delay one polarization component one-half wavelength relative to another, and a second waveguide segment that also differentially changes the amplitude of the light based on the polarization orientation. Also, an apparatus that includes a thin polarization converter that includes a thin first substrate that is substantially transparent to a wavelength of light, and a birefringent material deposited on one or more surfaces of the first substrate and oriented such that the polarization converter forms a half-wavelength birefringent plate for the light. Also, an apparatus having a first substrate surface, a second substrate surface, and a liquid crystal material between the first and second substrate surfaces to form a polarization converter.