Evanescent field sensors have shown promise for biological sensing applications. In particular, Silicon-on-Insulator (SOI)-nano-photonic based resonator sensors have many advantages for lab-on-chip diagnostics, including high sensitivity for molecular detection and compatibility with CMOS foundries for high volume manufacturing. We have investigated the optimum design parameters within the fabrication constraints of Multi-Project Wafer (MPW) foundries that result in the highest sensitivity for a resonator sensor.
View Article and Find Full Text PDFStandard silicon photonic strip waveguides offer a high intrinsic refractive index contrast; this permits strong light confinement, leading to compact bends, which in turn facilitates the fabrication of devices with small footprints. Sub-wavelength grating (SWG) based waveguides can allow the fabrication of low loss devices with specific, engineered optical properties. The combination of SWG waveguides with optical micro-resonators can offer the possibility of achieving resonators with properties different from the traditional SOI rings.
View Article and Find Full Text PDFA resonance-enhanced, defect-mediated, ring resonator photodetector has been implemented as a single unit biosensor on a silicon-on-insulator platform, providing a cost effective means of integrating ring resonator sensors with photodetectors for lab-on-chip applications. This method overcomes the challenge of integrating hybrid photodetectors on the chip. The demonstrated responsivity of the photodetector-sensor was 90 mA/W.
View Article and Find Full Text PDFIn this paper we demonstrate silicon on insulator (SOI) sub-wavelength grating (SWG) optical components for integrated optics and sensing. Light propagation in SWG devices is studied and realized with no cladding on top of the waveguide. In particular, we focused on SWG bends, tapers and directional couplers, all realized with compatible geometries in order to be used as building blocks for more complex integrated optics devices (interferometers, switches, resonators, etc.
View Article and Find Full Text PDFThis work presents simulation and experimental results of ultra-thin optical ring resonators, having larger Evanescent Field (EF) penetration depths, and therefore larger sensitivities, as compared to conventional Silicon-on-Insulator (SOI)-based resonator sensors. Having higher sensitivities to the changes in the refractive indices of the cladding media is desirable for sensing applications, as the interactions of interest take place in this region. Using ultra-thin waveguides (<100 nm thick) shows promise to enhance sensitivity for both bulk and surface sensing, due to increased penetration of the EF into the cladding.
View Article and Find Full Text PDFSilicon photonic biosensors are highly attractive for multiplexed Lab-on-Chip systems. Here, we characterize the sensing performance of 3 µm TE-mode and 10 µm dual TE/TM-mode silicon photonic micro-disk resonators and demonstrate their ability to detect the specific capture of biomolecules. Our experimental results show sensitivities of 26 nm/RIU and 142 nm/RIU, and quality factors of 3.
View Article and Find Full Text PDFWavelength-division-multiplexing (WDM) networks with wide channel grids and bandwidths are promising for low-cost, low-power optical interconnects. Wide-bandwidth, single-band (i.e.
View Article and Find Full Text PDFIEEE Trans Biomed Eng
March 2010
Optical methods are one of the painless and promising techniques that can be used for blood glucose predictions for diabetes patients. The use of thermally tunable vertical cavity surface-emitting lasers (VCSELs) as the light source to obtain blood absorption spectra, along with the multivariate technique partial least squares for analysis and glucose estimation, has been demonstrated. With further improvements by using data preprocessing and two VCSELs, we have achieved a clinically acceptable level in the physiological range in buffered solutions.
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