Microring resonators with circular element inner-wall gratings for enhanced sensing

We suggest that implementation of a circular element second order Bragg grating 1D photonic crystals into the inner-wall of silicon-on-insulator microring resonators increases the light-matter interaction strength and device free spectral range. Introduction of a specifically tailored grating changes the quality factor of a selected resonance and modulates the losses of the system, leading to the presence of longitudinal resonant air and dielectric Bloch modes. This phenomenon can be harnessed for the development of a self-referenced sensor that is immune to changes in ambient temperature and is well suited for both biomolecule and hydrogen gas exposure sensing. The recent results on numerical modeling, lithographic fabrication, and characterization of microring resonators with circular elements on inner-wall are presented.