  We study spin transport of holes through stubless or stubbed waveguides
modulated periodically by diluted magnetic semiconductor (DMS) sections of
width b1 . Injected holes of up (down) spin feel a periodically modulated
barrier (well) potential in the DMS sections and have different transmission
(T) coefficients. T oscillates with b1 for spin-down and decreases fast for
spin-up holes while the relative polarization Pr depends nearly periodically on
the stub height. Using asymmetric stubs leads to a nearly square-wave pattern
in T and to wide plateaus in Pr . T oscillates with the length between the DMS
sections. With two DMS sections per unit, T shows periodically wide gaps for
spin-down holes when a DMS width is varied. The results can be used to create
efficient spin filters.
