2D Grating Coupler Induced Polarization Crosstalk in Coherent Transceivers for Next Generation Data Center Interconnects

We investigate fundamental properties of polarization-splitting/combining 2D grating couplers for silicon photonic coherent transceivers. Linear cross-polarization related polarization crosstalk causes signal non-orthogonality. The relevance of these effects is illustrated in a 16-QAM experiment.