A phase-interrogation approach for the bulk refractive index sensing based on a silicon-on-insulator (SOI) ring resonator is introduced.The rapid phase variation around the resonance of the ring resonator is interrogated, and a single-sideband generation and coherent ALOE VERA 50MG detection technology is adopted for the phase measurement.In GLOSSY LIPSTICK ROSE FALLS #516 the proposed approach, most of the intensity noise can be shielded, which leads to an ultra-stable reading for the phase signals.A sensitivity of 6 × 103 rad/RIU and a detection limit of 2.5 × 10-6 RIU are demonstrated.