Improving the performance of silicon photonic rings, disks, and Bragg gratings for use in label-free biosensing

Silicon photonics biosensors continue to be an area of active research, showing the potential to revolutionize Labon-Chip applications ranging from environmental monitoring to medical diagnostics. As near-infrared light propagates through nano-scale silicon wires on an SOI chip, a portion of the light resides outside the waveguide and interacts with biomolecules and the biological matrix on the waveguide’s surface. This capability makes silicon photonics an ideal platform for label-free biosensing. Additionally, the SOI platform is compatible with standard CMOS fabrication processes, facilitating manufacturing at the economies of scale offered by today’s foundries. In this paper, we describe our efforts to improve the performance of SOI-based biosensors—specifically, TE and TM mode microring resonators, thin waveguide resonators, sub-wavelength grating resonators, as well as strip and slot Bragg gratings. We compare device performance in terms of sensitivity, intrinsic limit of detection, and their potential for biosensing applications in Lab-on-Chip systems.