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.
