Integrated optic TE/TM pass polarizers using resonant coupling between ITO thin film lossy modes and dielectric waveguide modes

The resonant coupling between the lossless dielectric waveguide modes and the lossy modes supported by the absorbing indium–tin oxide (ITO) film is analyzed theoretically. It is observed that by changing the thickness of an ITO cladding layer placed above the planar dielectric waveguide, the TE or TM propagating modes may be selectively attenuated. This polarization effect can be used to design a TE or TM pass polarizer. Further it is also proposed that an electro-optic buffer layer inserted between the waveguide and ITO film can be used to design a high extinction ratio integrated optic polarizer at wavelength of 1.3 μm. A polarizer (both TE and TM pass) with extinction ratio of about 254 dB and insertion loss of about 10 dB can be easily designed for a 1 mm of its length.