Foundry-fabricated grating coupler demultiplexer inverse-designed via fast integral methods
Silicon photonics is an emerging technology which, enabling nanoscale manipulation of light on chips, impacts areas as diverse as communications, computing, and sensing. Wavelength division multiplexing is commonly used to maximize throughput over a single optical channel by modulating multiple data streams on different wavelengths concurrently. Traditionally, wavelength (de)multiplexers are implemented as monolithic devices, separate from the grating coupler, used to couple light into the chip. This paper describes the design and measurement of a grating coupler demultiplexer—a single device which combines both light coupling and demultiplexing capabilities. The device was designed by means of a custom inverse design algorithm which leverages boundary integral Maxwell solvers of extremely rapid convergence as the mesh is refined. To the best of our knowledge, the fabricated device enjoys the lowest insertion loss reported for grating demultiplexers, small size, high splitting ratio, and low coupling-efficiency imbalance between ports, while meeting the fabricability constraints of a standard UV lithography process.
© The Author(s) 2022. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Received 05 May 2021; Accepted 21 February 2022; Published 23 March 2022. O.P.B. gratefully acknowledges support from NSF under contracts DMS-1714169 and DMS-2109831, from AFOSR under contract FA9550-21-1-0373, from DARPA under contract HR00111720035, and from the NSSEFF Vannevar Bush Fellowship under contract number N00014-16-1-2808. C.S. gratefully acknowledges support by the National Science Foundation under contracts CCF-1849965 and CCF-2047433, and AFOSR under contract FA9550-20-1-0087. The authors gratefully acknowledge financial support from Caltech RI2 Program under contract CIT-2021RI2-1. Data availability: The design parameters that characterize the proposed device as well as an alternate device requiring smaller minimum feature sizes, are included in the Supplementary Notes 2 and 4. The data used to produce the figures can be obtained upon reasonable request from the corresponding author. Code availability: The computer codes used for simulation and design are available from the corresponding author upon reasonable request. Contributions: C.S. and O.P.B. developed the inverse design framework used, and utilized it to obtain the proposed design. C.S., A.K., A.D.W., and S.A.H. developed the testing methodology including incorporating additional test structures for decoupling the losses of the device itself from those of the measurement setup. A.K., A.D.W., and C.S. characterized the fabricated design experimentally. C.S., A.K., and O.P.B. analyzed the measurement results and compared them against numerical simulations. All authors contributed to the preparation and review of the manuscript. The authors declare no competing interests. Peer review information: Communications Physics thanks Ke Xu, Daniele Melati, and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.
Sideris, C., Khachaturian, A., White, A.D. et al. Author Correction: Foundry-fabricated grating coupler demultiplexer inverse-designed via fast integral methods. Commun Phys 5, 98 (2022). https://doi.org/10.1038/s42005-022-00877-4
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Erratum - s42005-022-00877-4.pdf
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