Polarization rotation Bragg diffraction using Si wire waveguide grating and polarization rotator.

We report polarization independent Bragg grating wavelength filter with high diffraction efficiency. A rib waveguide polarization rotator and antisymmetric grating structure for fundamental to first order diffraction are used to generate the polarization rotation Bragg diffraction. The diffraction efficiencies and peak wavelengths become the same for two orthogonal input polarizations. Strong diffraction is attained easily. The concept was verified by simulation and experiment. Polarization independent band-pass filter consisting of polarization beam splitter and polarization rotation Bragg diffraction was experimentally demonstrated.