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An Optimization Framework for Silicon Photonic Evanescent-Field Biosensors Using Sub-Wavelength Gratings.
Lauren S Puumala1,2, Samantha M Grist1,2,3, Kithmin Wickremasinghe4
1School of Biomedical Engineering, University of British Columbia, 251-2222 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
Biosensors
|October 27, 2022
Summary
This study introduces robust "fishbone" sub-wavelength grating (SWG) silicon photonic (SiP) microring resonators for biosensing. These improved SWG designs offer high sensitivity and a more durable alternative for portable diagnostics.
Area of Science:
- Photonics and Biosensing
- Materials Science and Engineering
Background:
- Silicon photonic (SiP) evanescent-field biosensors offer lab-quality diagnostics in portable formats.
- Conventional SiP sensors have limitations in sensitivity and robustness, particularly those using sub-wavelength gratings (SWGs).
Purpose of the Study:
- To investigate and optimize a novel
- fishbone
- SWG waveguide geometry for SiP microring resonator biosensors.
- To enhance the robustness and sensitivity of SiP biosensors for practical applications.
Main Methods:
- Numerical simulations were employed to optimize the fishbone-style SWG waveguide geometry.
- Ring resonator sensors were fabricated using the optimized waveguides.
- Experimental measurements were performed to evaluate sensor performance in the O-band and C-band.
Main Results:
- Optimized fishbone SWG resonators demonstrated bulk sensitivities up to 349 nm/RIU (O-band) and 438 nm/RIU (C-band).
- Intrinsic limits of detection were as low as 5.1 × 10-4 RIU (O-band) and 7.1 × 10-4 RIU (C-band).
- The fishbone design significantly improved the robustness of SWG-based SiP sensors.
Conclusions:
- Fishbone SWG microring resonators present a robust and highly sensitive platform for SiP biosensing.
- This design offers a promising, durable alternative to conventional SWG waveguides for scalable and portable diagnostic devices.
- The optimized fishbone SWG resonators achieve state-of-the-art performance, suitable for advanced biosensing applications.
