Summary: | Rapid pathogenic detection of Escherichia coli (E. coli) bacteria is vitally important in medical and pharmaceutical companies, environmental monitoring, and biomedical research. In this work, a double-decker ring resonator (DDRR) with resonant mode numbers of 9 and 11 is fabricated from a nano-core slab waveguide from Si3N4 placed on a coring 7980 silica substrate is used for detection of E. coli bacterium in water. The sensor’s performance is studied for four waveguide layouts, and the effect of evanescent field penetration depth on volume sample is studied. Results simulated using the signal flow graph method and MATLAB software. The maximum sensitivity of the DDRR sensor is measured to be 605 nm/RIU, which corresponds to high-resolution sensing of 1.82 × 10–6 RIU. Results show that increasing the height of the superstrate sensing window waveguide to four times the height of the core layer contributes to improve the sensitivity. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
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