We investigate the possibility of constructing nanostructure waveguides using Si‐based materials. For this purpose we evaluate the dielectric function of strain‐symmetrized (Si)10−n/(Ge)nstrained‐layer superlattices (SLS’s) withn=3, 5 and 7, and (Si)6/(Ge)4SLS coherently grown on a Si(001) surface, as well as that for bulk Si1−n/10Gen/10alloys withn=3, 5 and 7, and bulk Si. In particular we explore the possibility of constructing waveguides using the materials (Si)6/(Ge)4SLS, coherently grown on a Si(001) surface, and bulk Si. We investigate the case of planar waveguide structure, giving results concerning the propagation and penetration of the transverse magnetic modes. ©1995 American Institute of Physics.