Polarization independent optical filter using interwaveguide TE↔TM conversion

Abstract
We report the first demonstration of a polarization-independent, integrated-optic wavelength filter. Polarization-independent filtering is achieved via wavelength selective TE↔TM conversion between a pair of mismatched Ti-diffused lithium niobate waveguides. A peak coupling efficiency of ∼75% and 5-Å filter bandwidth have been achieved.