Silicon-on-insulator-based eye-shaped microring resonator for label-free detection of anemia

In this work, we propose an eye-shaped microring resonator (E-SMRR)-based photonic biosensor on a silicon-on-insulator (SOI) substrate. The device is modeled using variational finite-difference time-domain (Var FDTD) simulations. Furthermore, the Mason's gain rule is employed to analytically determine the optical transfer function for the drop port of the E-SMRR system. The proposed E-SMRR biosensor offers a bulk sensitivity of 460.829 nm/RIU, an FSR of 27.535 nm, a quality factor of 1070.677, and a figure of merit equal to 341.308. Additionally, the device has been evaluated for its ability to detect the anemia by assessment of varying hemoglobin concentrations, demonstrating a significant shift in resonant wavelength with a high sensitivity of 7.378×10^-2nm/gL^-1 and an intrinsic limit of detection (iLOD) of 4.325×10^-3RIU. Thus, the design of the proposed E-SMRR biosensor on the SOI substrate is promising for the development of futuristic on-chip optical biosensors.