Polarization transparency for silicon photonics

We experimentally demonstrate the ability to couple any polarization state from a fiber to the TE-mode of a single waveguide in an integrated silicon photonics circuit. We achieved this by combining a 2D-grating coupler and two tunable Mach-Zehnder Interferometers (MZI) into a polarization adapter. We obtain less than ±0.6 dB standard deviation across all input polarization states at a wavelength of 1.55 μm.