A fiber-optic polarizer comprising the combination of an optical fiber having a polarization-holding core and cladding with different refractive indices and forming a single-mode guiding region, the guiding region being offset from the center of gravity of the fiber section and located sufficiently close to the surface of one side of the fiber, along a selected length of the fiber, to expose the evanescent field of the guiding region at the surface of the one side to allow coupling to a contiguous medium, the outer surface of the fiber having a non-circular cross-section with a predetermined geometric relationship to the guiding region and a pair of orthogonal polarization axes therein so that the location of the guiding region and the orientation of the axes can be ascertained from the geometry of the outer surface, and a coating of indium on at least the one side of the fiber where the evanescent field is exposed so that light waves having undesired polarizations are attenuated by the indium coating.