Numerical analysis of polarization splitter based on vertically coupled microring resonator

The performance of a polarization splitter based on vertically coupled microring resonator is rigorously investigated by a combination of a 3D full vectorial film mode matching method with a 3D full vectorial coupled mode theory. The spectral responses of the structure for TE and TM mode are calculated, together with eigenmodes of uncoupled waveguides and scattering matrix of coupling region. The result shows that the response of microring resonator is indeed strongly polarization dependent and the resonance wavelengths are different for TE and TM mode. Such property allows for the design of wavelength-sensitive integrated polarization splitter. The influence of geometrical parameters on splitting ratio is investigated and the results indicate that the structure can have a splitting ratio greater than 20dB at 1.55 mu m. (c) 2006 Optical Society of America.