2017/05/31 by Andrew Michaels, Eli Yablonovitch · 1 citation
Physics and Astronomy · #physics.optics #physics.app-ph
paper · pdf · doi:10.1364/oe.26.004766
9 pages, 9 figures. Updated to fix author name. This preprint has since been updated and accepted for publication in Optics Express: https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-4-4766
arxiv created 2018/03/02 · arxiv updated 2018/03/14
Efficient coupling between integrated optical waveguides and optical fibers is essential to the success of integrated photonics. While many solutions exist, perfectly vertical grating couplers which scatter light out of a waveguide in the direction normal to the waveguide's top surface are an ideal candidate due to their potential to reduce packaging complexity. Designing such couplers with high efficiency, however, has proven difficult. In this paper, we use electromagnetic inverse design techniques to optimize a high efficiency two-layer perfectly vertical silicon grating coupler. Our base design achieves a chip-to-fiber coupling efficiency of over 99% (-0.04 dB) at 1550 nm. Using this base design, we apply subsequent constrained optimizations to achieve vertical couplers with over 96% efficiency which are fabricable using a 65 nm process.