Plasmon-polariton polarizers on the surface of single-mode channel optical waveguides (OWGs) in lithium niobate crystals have been studied in detail. An original technology for manufacturing polarizers in a single technological cycle has been developed. A polarizer consists of a metal (aluminum) film and a dielectric (Al2O3) buffer layer. An optimum polarizer configuration is found for single-mode channel OWGs matched to a standard optical fiber (SMF-28). A prototype polarizer was manufactured, which was characterized by a polarization extinction ratio of 19 dB/mm and insertion losses on a level of 0.1 dB/mm.