Abstract: This is a fabrication process for Y-branch nickel/zinc-indiffused polarization splitters on lithium niobate. The fabrication technology needs only two nickel/zinc indiffusions; one at a high temperature and the other at a lower temperature. Nickel/zinc-indiffused waveguides can support single-ordinary, single-extraordinary, and random polarization waves depending on the fabrication process parameters. High extinction ratios can be achieved due to the inherent single-polarization of the waveguides. The splitting ratios of the TE and TM modes are sufficiently high for practical applications.