Polarized micro-ring resonator for miniaturization of the Rydberg atomic system

Rydberg atomic sensing technology can take the measurement of the electromagnetic field into the optical frequency, showing excellent characteristics such as high accuracy, high sensitivity, ultra-wideband measurement, and self-calibration and is quickly becoming one of the international research hotspots. The laser system is the key to realizing the excitation of a Rydberg atom, and also one of the bottlenecks to miniaturizing the sensing system. Thereby, laser polarization and linewidth can greatly impact the energy level transition efficiency. In this paper, a polarized micro-ring resonator, including a micro-ring resonator and a three-waveguide polarization beam splitter, is designed based on the phase-matching condition. With this structure, polarization selection and frequency filtering can be easily realized at the micrometer scale. The results show that the TM mode can get good spectral response, and the TE mode is suppressed below −12dB at the drop port. This on-chip integrated structure is one of the effective ways to miniaturize the Rydberg atomic system.