Analysis of Silicon Clad Optical Waveguide for High Extinction Ratio TE/TM Pass Polarizers using Resonant Coupling between Guided Modes and Lossy Modes

Attenuation characteristics of a planar silicon-clad ion exchange glass waveguide structure are investigated theoretically at the optical wavelength of 0.6328 μm. An oscillatory behaviour of the attenuation curves is noticed in the proposed four layer structure. It is observed that by varying the thickness of silicon cladding layer, the TE or TM propagating modes may be selectively attenuated. This characteristic can be used to design a high extinction ratio and low insertion loss TE or TM pass polarizer. For the analysis of both polarizations, effective indices are calculated at various thicknesses of Silicon cladding layer using Transfer Matrix Method (TMM). At an optimum Silicon thickness, polarizer parameters like insertion loss and extinction ratio are calculated and tabulated. This paper provides rigorous analysis for silicon clad waveguide polarizer parameters for TE as well as TM polarization using same structure. A TM pass polarizer with extinction ratio of about 690 dB and insertion loss of about 2.8 dB and a TE pass polarizer with extinction ratio of about 289 dB and insertion loss of about 1.5 dB is proposed for a length of 1mm.