Disk-loaded silicon micro-ring resonator for high-Q resonance

By adding two disks to a standard silicon micro-ring resonator, a very high-quality factor (Q) asymmetric resonance with Q values as high as 7.773 × 105 and slope rates in excess of 880 dB/nm can be achieved. A circuit model has been proposed for this device based on which an analysis has been carried out that can predict the effect of reflections in the coupling components. Depending on the coupling coefficient between the disks and the micro-ring resonator (MRR), it is possible to use this design in three regimes, with different spectral features. Moreover, it is shown that the disks introduce a discontinuity in the transmission spectrum and the relative positioning of the disks in the ring provides a new degree of freedom in the design step. The proposed device features a high extinction ratio (ER) around 1550 nm and could be fabricated in any standard silicon photonics technology without requiring any extra materials or processing steps. The proposed resonator has a high sensitivity of Δλ Res (nm)/Δn > 299 nm/RIU, which makes it suitable for sensing applications and efficient modulators.