Embedded metallic focus grating for silicon nitride waveguide with enhanced coupling and directive radiation

作者：Wang Lingyun^*; Wang Youmin; Zhang Xiaojing

来源：Optics Express, 2012, 20(16): 17509-17521.

DOI：10.1364/OE.20.017509

We design a compact embedded metallic elliptical focus grating coupler based on gold or silver that efficiently interconnects free space with silicon nitride waveguide at 632.8nm wavelength. The 3D far-field radiation pattern for the proposed grating coupler shows much higher gain and directivity towards free space coupling than that of the etched grating coupler. Specifically the free space transmission efficiency achieves 65% for silver grating coupler. It can also further enhance the fluorescence signal detection for Cy-5 fluorophore by isolating peak diffraction angle for 10 degrees. The dense system integration capability shows the application potential for on-chip interfacing sub-wavelength light processing circuits and near-field fluorescent biosensors with far-field detection of superb radiation directivity and coupling efficiency.

• 出版日期2012-7-30