Polarization splitters are important functions in integrated-optic devices for managing polarization diversity. We present the fabrication and characterization of polymer waveguide couplers with localized anisotropic segments in the coupling region. The core of the waveguide is made of a polymerizable liquid crystal that is thermally patterned into isotropic and anisotropic regions before etching. For an appropriate coupling length, the coupler behaves as a polarization splitter: the horizontal polarization remains on the direct waveguide, while the vertical polarization is totally transferred to the coupled waveguide. This fabrication technique and the resulting couplers are useful elements for the development of polymer integratedoptic devices.