Enhanced sensitivity and measurement range SOI microring resonator with integrated one-dimensional photonic crystal

We present a silicon-on-insulator microring resonator-based refractive index sensor with enhanced sensitivity and measurement range. Both improvements are achieved by integrating a 1D photonic crystal inside the microring waveguide. A photonic crystal is formed by periodically patterning, partially etching the rectangular perforations. Sensor performance is numerically analyzed for various combinations of perforation depth and length, each of which maintains a constant resonance wavelength. Our findings show that, while deeper perforations result in a larger bulk refractive index sensitivity, the optimal design exhibiting the smallest limit of detection can be obtained at some intermediate value, depending on the leading term in sensor resolution. In addition to theoretical analysis, we present an experimental demonstration of a fabricated microring resonator with 120 nm height perforations.