Differential Polarization Delay in Coupled-Resonator Optical Waveguides

An integrated device capable of dynamically controlling the differential delay between two orthogonally polarized data channels is presented. The polarization-selective delay is induced by exploiting waveguide birefringence in a ring-resonator coupled resonator optical waveguide. A prototype realized in silicon-oxynitride technology is employed to manage the differential delay between two polarization-division-multiplexed channels modulated up to 10 Gb/s over several bit-slots. Reconfiguration is achieved by thermo-optic effect with 1-ps delay accuracy. Back-to-back and propagated bit-error-rate measurements show minor deterioration of the signal with negligible polarization crosstalk.