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Optimization of Silicon Nitride Waveguide Platform for On-Chip Virus Detection.
Raghi S El Shamy1, Mohamed A Swillam2, Xun Li1
1Department of Electrical and Computer Engineering, Faculty of Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada.
Sensors (Basel, Switzerland)
|February 15, 2022
Summary
Silicon nitride strip waveguides offer sensitive, selective virus detection. Optimized for lower wavelengths, these optical sensors provide a cost-effective alternative to PCR, enabling rapid and mass-producible diagnostic devices.
Area of Science:
- Photonics and Nanotechnology
- Biomedical Sensing
- Optical Engineering
Background:
- Integrated optical sensors offer advantages over traditional methods like PCR for virus detection.
- Refractive index (RI) sensors provide cost-effective, mass-producible, and compact devices for rapid analysis.
- Functionalizing waveguide surfaces with antibodies enhances selectivity for specific viruses.
Purpose of the Study:
- To perform a rigorous sensitivity analysis of silicon nitride on silicon dioxide strip waveguides for virus detection.
- To determine optimal waveguide dimensions for maximum sensitivity across visible to mid-infrared wavelengths.
- To compare the performance of strip waveguides with slot waveguides for biosensing applications.
Main Methods:
- Numerical analysis using a finite difference eigenmode (FDE) solver to determine single-mode dimensions.
- Optimization of waveguide dimensions to maximize sensitivity to virus layers at various wavelengths.
- Design and simulation of balanced Mach-Zehnder interferometer (MZI) sensors and fiber edge coupling.
Main Results:
- Silicon nitride strip waveguides operating at lower wavelengths (e.g., 450 nm) exhibit maximum waveguide sensitivity (Swg) and figure of merit (FOM).
- Optimized MZI sensors achieved high FOM values (500–1231 RIU-1) at λ = 450 nm.
- Designed edge coupling demonstrated insertion loss (IL) of 4.1 dB at λ = 450 nm, with high coupling efficiencies.
Conclusions:
- Silicon nitride strip waveguides are optimal for virus detection, offering high sensitivity and FOM, particularly at shorter wavelengths.
- The developed optical sensors are suitable for detecting various viruses due to their adaptability to different sizes and refractive indices.
- The study presents a viable, efficient, and cost-effective optical sensing platform for advanced virus detection systems.
