Polarization-dependent waveguide coupling utilizing single-negative materials

It is shown that if a single-negative (SNG) material layer is included between two parallel waveguides of a directional coupler, we can obtain such supermodes that the symmetric mode propagates faster than the antisymmetric mode for one polarization component of input waves while the antisymmetric mode travels faster than the symmetric mode for the other polarization component. Utilizing this feature, we propose a new kind of polarization beam splitter whose polarization-dependent characteristics are originated not from the material birefringence, but from polarization-dependent continuity conditions at media interfaces between conventional materials and the SNG media.