Resonant tunneling three-waveguide polarization splitter

A design for a novel and highly efficient all-dielectric, three-waveguide polarization splitter based on the phenomenon of resonant tunneling is proposed. By considering a glass waveguide structure with an intermediate high-index guiding layer (such as silicon), it is shown that extinction ratios better than -33 dB in both the outer waveguides at a particular thickness of the high-index layer can be obtained. The tolerance required with respect to the separation between the middle and outside guides and the thickness of the high-index layer of such a device is estimated. The design should be of interest in the realization of in-line fiber-optic polarization splitters and in integrated optics