Racetrack ring resonator based refractive index sensor for biosensing application

In this paper, a racetrack ring resonator (RRR)-based refractive index (RI) sensor on a silicon-on-insulator (SOI) platform is designed for the development of biosensing applications. It features two straight rib bus waveguides with a circular shape ring in the center, with an elongated straight section, which enhances coupling efficiency and light confinement. The fundamental TE<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> mode is coupled from the rib waveguide to the circular ring at the resonance wavelength, enabling its application in sensing. The time-efficient finite difference time domain (FDTD) method has been employed to optimize the performance metrics of the proposed sensor and utilize it in the C band (1500-1600) nm optical source. The suggested sensor has great potential in healthcare for early disease detection of cancer cells. The performance matrices are improved by optimizing the structural parameters. The proposed sensor has achieved a foremost quality factor, sensitivity, and figure of merit 3332, 102 nm/RIU, and 201 RIU<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">–1</sup> respectively.