Micro-dispenser-based optical packaging scheme for grating couplers
Date
2023-04-13
Journal Title
Journal ISSN
Volume Title
Publisher
Optics Letters
Abstract
Due to their sub-millimeter spatial resolution, ink-based additive manufacturing tools are typically considered less attractive than nanophotonics. Among these tools, precision micro-dispensers with sub-nanoliter volumetric control offer the finest spatial resolution: down to 50 µm. Within a sub-second, a flawless, surface-tension-driven spherical shape of the dielectric dot is formed as a self-assembled µlens. When combined with dispersive nanophotonic structures defined on a silicon-on-insulator substrate, we show that the dispensed dielectric µlenses [numerical aperture (NA) = 0.36] engineer the angular field distribution of vertically coupled nanostructures. The µlenses improve the angular tolerance for the input and reduces the angular spread of the output beam in the far field. The micro-dispenser is fast, scalable, and back-end-of-line compatible, allowing geometric-offset-caused efficiency reductions and center wavelength drift to be easily fixed. The design concept is experimentally verified by comparing several exemplary grating couplers with and without a µlens on top. A difference of less than 1 dB between incident angles of 7° and 14° is observed in the index-matched µlens, while the reference grating coupler shows around 5 dB contrast.
Description
This article was originally published in Optics Letters. The version of record is available at: https://doi.org/10.1364/OL.486595. © 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement: https://doi.org/10.1364/OA_License_v2#VOR-OA.
Keywords
Citation
S. M. Zia Uddin, Ellen Gupta, Masudur Rahim, Zi Wang, Yang Du, Kaleem Ullah, Craig B. Arnold, Mark Mirotznik, and Tingyi Gu, "Micro-dispenser-based optical packaging scheme for grating couplers," Opt. Lett. 48, 2162-2165 (2023)