Polarization rotator-splitters and controllers in a Si3N4-on-SOI integrated photonics platform

We demonstrate novel polarization management devices in a custom-designed silicon nitride (Si3N4) on silicon-on-insulator (SOI) integrated photonics platform. In the platform, Si3N4 waveguides are defined atop silicon waveguides. A broadband polarization rotator-splitter using a TM0-TE1 mode converter in a composite Si3N4-silicon waveguide is demonstrated. The polarization crosstalk, insertion loss, and polarization dependent loss are less than -19 dB, 1.5 dB, and 1.0 dB, respectively, over a bandwidth of 80 nm. A polarization controller composed of polarization rotator-splitters, multimode interference couplers, and thin film heaters is also demonstrated. © 2014 Optical Society of America.