Polarization characteristics of compact SOI rib waveguide racetrack resonators

We report on the development of compact optical racetrack resonators on silicon-on-insulator (SOI) rib waveguides. We make use of large-cross-section waveguides instead of photonic wire waveguides. We fabricated resonators with bending radii down to 20 μm and characterized for both transverse-electric and transverse-magnetic polarizations. Different polarization characteristics were analyzed and related to the modal shape of the SOI waveguide. These compact resonators show large free spectral ranges (3.0 nm), high finesse (19), and Q-factor (28 000) values.