A high sensitive integrated optic serially coupled racetrack ring resonator based pressure sensor

This research work describes, a novel integrated optic serially coupled micro racetrack-ring resonator (SCRR) based pressure sensor. Racetrack-ring resonators of radius 5μm and 4μm are chosen to create the Vernier-effect. The resonators are optimized for large FSR and high Q-factor by Finite-Difference-Time-Domain (FDTD) Method. The resonators are coupled serially between input–output waveguides to design a SCRR. The SCRR is used as a sensing element and integrated on silicon diaphragm. The sensor follows the Photo-elastic effect principle. When the pressure is applied on sensing element, there is a change in the effective refractive-index of sensor and leads to a shift in the super resonant wavelength. The shift is proportional to an applied pressure. So, the change in applied pressure is observed as a resonant-wavelength shift. The stress analysis of sensor is examined by Finite-Element-Method, and the field propagation of SCRR is examined using the FDTD-method. This sensor provides, high sensitivity of 1.04 nm per 100 kPa and Q-factor of 14084. The sensor range is 0 to 300 kPa. •An IO serially coupled racetrackring resonator-based pressure sensor is reported.•Racetrackring resonators of radius 5μm and 4μm are chosen to create Vernier-effect.•These resonators are used in the design of serially coupled racetrackring resonator.•This pressure sensor works on the Photo-elastic effect principle.•Sensor analyzed using FEM and FDTD methods and sensitivity is 1.04nm per 100kPa.