Fluorescence detection is a commonly used technique to detect particles. Microscopes are used for the fluorescence detection of the micro-particles. However, the conventional microscopes are bulky. It is cumbersome to integrate all the equipment used for detection in one setup. They can be replaced by photonic chips for the detection of micro-particles such as cells. Most of the biological detection techniques require the utilization of the visible range of the spectrum. SiN as a waveguide material stands out for biological applications due to its transparency in the visible spectrum. Specifically designed grating couplers can be exploited to focus from inside SiN waveguides at a designated location above the chip. Those SiN focusing grating couplers can mimic microscope objectives for on-chip biological detection applications such as fluorescence and Raman spectroscopy. In this report, we present a 2D SiN focusing grating coupler. We study the effect of the grating design on the focus properties of visible light using finite-difference time-domain simulations.

Date Published: 13 May 2016
PDF: 15 pages
Proc. SPIE 9891, Silicon Photonics and Photonic Integrated Circuits V, 98911L (13 May 2016); doi: 10.1117/12.2227740

Published in SPIE Proceedings Vol. 9891:
Silicon Photonics and Photonic Integrated Circuits V
Laurent Vivien; Lorenzo Pavesi; Stefano Pelli, Editor(s)