Polarization converters based on ring-resonator phase-shifters

In this letter, novel devices based on ring-resonator phase-shifters are proposed for the realization of efficient polarization converters with periodical spectral response. The main spectral properties of several architectures, including parallel-coupled and directly coupled ring-resonators, are analytically investigated and conditions for complete polarization rotation are derived. The exploitation as polarization interleavers and polarization splitters/combiners is also briefly discussed.