Z-Domain Modeling and Performance Evaluation of Triple Optical Ring Resonator With Embedded Bragg Gratings as Optical Filter and Biosensor

This article introduces a novel Bragg grating-integrated triple optical ring resonator (TORR) design, which functions as an optical filter and a high-precision biosensor, demonstrating versatility across photonic and biomedical applications. A delay-line signal processing approach, along with Z-domain analysis, is employed to derive the mathematical formulation of the system. The integration of high-contrast optical Bragg gratings within the waveguide significantly enhances wavelength selectivity and sensitivity. The proposed configuration improves the interaction between guided light and the surrounding medium, thus increasing the device’s sensitivity to refractive index variations. Simulation studies, supported by finite-difference time-domain (FDTD) analysis, validate the performance of the proposed configuration. The device demonstrates a superior spectral response with a free spectral range (FSR) of 111.6 THz and high sensitivities of 411.738 and 462.047 nm/refractive index unit (RIU) for blood components and cancer cells, confirming its potential for optical and biomedical sensing applications. The combination of advanced structural design and rigorous analytical modeling underscores the potential of this integrated photonic device in future high-precision sensing and signal processing applications.