Silicon-on-insulator microring resonators for photonic biosensing applications

Silicon-on-insulator microring resonators have proven to be an excellent platform for label-free nanophotonic biosensors. The high index contrast of the silicon-on-insulator waveguides allows for fabrication of micrometer size sensors. Their small size combined with high sensitivity make them ideal candidates for integration in sensing arrays as a multiplexed DNA detection platform. By chemically modifying the sensor surface, the microrings can provide sequence selective DNA detection. However, the high index contrast also limits the quality of the resonances by introducing an intrinsic mode-splitting by coupling the degenerate resonator modes. This severely deteriorates the quality of the output signal. The quality of the resonances is of utmost importance to determine the performance of the microrings as a biosensor. We will suggest an integrated interferometric approach to give access to the unsplit, high-quality normal modes of the microring resonator

Implementation of surface gratings for reduced coupling noise in silicon-on-insulator circuits

Coupling light into a silicon-on-insulator photonic chip has always been the first hurdle to overcome when using photonic integrated circuits. For applications that require robust, low-noise performance, and high degree of multiplexing, flood illuminating an array of vertical grating couplers is a promising approach to couple input light into the chip waveguides. This technique provides a very high alignment tolerance and allows simultaneous excitation of multiple waveguides for rapid parallel readout. However, parasitic reflections of the coupled light on the chip substrate introduce interferences and limit the device performance. We investigate the use of grating structures implemented on the chip surface to limit these parasitic signals and demonstrate a significant reduction of the coupling noise

Silicon photonics biosensing: different packaging platforms and applications

We present two different platforms integrating silicon photonic biosensors. One is based on integration with reaction tubes to be compatible with traditional lab approaches. The other uses through-chip fluidics in order to achieve better mixing of the analyte