{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,14]],"date-time":"2026-02-14T06:55:14Z","timestamp":1771052114463,"version":"3.50.1"},"reference-count":22,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2023,5,11]],"date-time":"2023-05-11T00:00:00Z","timestamp":1683763200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>An efficient optical coupler to transfer the signal between an optical fiber and a silicon waveguide is essential for realizing the applications of silicon photonic integrated circuits such as optical communication and optical sensing. In this paper, we numerically demonstrate a two-dimensional grating coupler based on a silicon-on-insulator platform to obtain completely vertical and polarization-independent couplings, which potentially ease the difficulty of packaging and measurement of photonic integrated circuits. To mitigate the coupling loss induced by the second-order diffraction, two corner mirrors are respectively placed at the two orthogonal ends of the two-dimensional grating coupler to create appropriate interference conditions. Partial single-etch is assumed to form an asymmetric grating to obtain high directionalities without a bottom mirror. The two-dimensional grating coupler is optimized and verified with finite-difference time-domain simulations, achieving a high coupling efficiency of \u22121.53 dB and a low polarization-dependent loss of 0.015 dB when coupling to a standard single-mode fiber at approximately 1310 nm wavelength.<\/jats:p>","DOI":"10.3390\/s23104662","type":"journal-article","created":{"date-parts":[[2023,5,12]],"date-time":"2023-05-12T01:30:29Z","timestamp":1683855029000},"page":"4662","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Design of a Completely Vertical, Polarization-Independent Two-Dimensional Grating Coupler with High Coupling Efficiency"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4725-7818","authenticated-orcid":false,"given":"Chung-Chih","family":"Lin","sequence":"first","affiliation":[{"name":"Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan"},{"name":"Artilux Inc., Hsinchu 30288, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yen-Cheng","family":"Lu","sequence":"additional","affiliation":[{"name":"Artilux Inc., Hsinchu 30288, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yu-Hsuan","family":"Liu","sequence":"additional","affiliation":[{"name":"Artilux Inc., Hsinchu 30288, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Likarn","family":"Wang","sequence":"additional","affiliation":[{"name":"Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2553-3324","authenticated-orcid":false,"given":"Neil","family":"Na","sequence":"additional","affiliation":[{"name":"Artilux Inc., Hsinchu 30288, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,5,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1302","DOI":"10.1364\/OL.28.001302","article-title":"Nanotaper for compact mode conversion","volume":"28","author":"Almeida","year":"2003","journal-title":"Opt. Lett."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"5026","DOI":"10.1364\/OE.24.005026","article-title":"Fiber-Chip Edge Coupler with Large Mode Size for Silicon Photonic Wire Waveguides","volume":"24","author":"Papes","year":"2016","journal-title":"Opt. Express"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"397","DOI":"10.1016\/S0167-9317(04)00143-1","article-title":"Efficient Fiber-to-Waveguide Coupling by a Lens on the End of the Optical Fiber Fabricated by Focused Ion Beam Milling","volume":"73\u201374","author":"Schiappelli","year":"2004","journal-title":"Microelectron. Eng."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2749","DOI":"10.1364\/OL.29.002749","article-title":"Compact Efficient Broadband Grating Coupler for Silicon-on-Insulator Waveguides","volume":"29","author":"Taillaert","year":"2004","journal-title":"Opt. Lett."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"21800","DOI":"10.1364\/OE.22.021800","article-title":"Efficient Silicon Nitride Grating Coupler with Distributed Bragg Reflectors","volume":"22","author":"Zhang","year":"2014","journal-title":"Opt. Express"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1395","DOI":"10.1109\/LPT.2013.2266132","article-title":"CMOS-Compatible Polarization Splitting Grating Couplers with a Backside Metal Mirror","volume":"25","author":"Zaoui","year":"2013","journal-title":"IEEE Photonics Technol. Lett."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"474","DOI":"10.1364\/OL.43.000474","article-title":"Low-Loss Two-Dimensional Silicon Photonic Grating Coupler with a Backside Metal Mirror","volume":"43","author":"Luo","year":"2018","journal-title":"Opt. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"4663","DOI":"10.1109\/JLT.2017.2755673","article-title":"Perpendicular Grating Coupler Based on a Blazed Antiback-Reflection Structure","volume":"35","author":"Watanabe","year":"2017","journal-title":"J. Light. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"7904709","DOI":"10.1109\/JPHOT.2019.2926823","article-title":"2-D Grating Couplers for Vertical Fiber Coupling in Two Polarizations","volume":"11","author":"Watanabe","year":"2019","journal-title":"IEEE Photonics J."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"4190","DOI":"10.1364\/OL.40.004190","article-title":"High-Directionality Fiber-Chip Grating Coupler with Interleaved Trenches and Subwavelength Index-Matching Structure","volume":"40","author":"Benedikovic","year":"2015","journal-title":"Opt. Lett."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"3439","DOI":"10.1364\/OL.42.003439","article-title":"L-Shaped Fiber-Chip Grating Couplers with High Directionality and Low Reflectivity Fabricated with Deep-UV Lithography","volume":"42","author":"Benedikovic","year":"2017","journal-title":"Opt. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"5081","DOI":"10.1364\/OL.44.005081","article-title":"High-Efficiency Apodized Bidirectional Grating Coupler for Perfectly Vertical Coupling","volume":"44","author":"Zhang","year":"2019","journal-title":"Opt. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1290","DOI":"10.1364\/OL.35.001290","article-title":"Highly Efficient Nonuniform Grating Coupler for Silicon-on-Insulator Nanophotonic Circuits","volume":"35","author":"Tang","year":"2010","journal-title":"Opt. Lett."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1156","DOI":"10.1109\/LPT.2010.2051220","article-title":"Apodized Waveguide Grating Couplers for Efficient Coupling to Optical Fibers","volume":"22","author":"Chen","year":"2010","journal-title":"IEEE Photonics Technol. Lett."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"4766","DOI":"10.1364\/OE.26.004766","article-title":"Inverse Design of near Unity Efficiency Perfectly Vertical Grating Couplers","volume":"26","author":"Michaels","year":"2018","journal-title":"Opt. Express"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1495","DOI":"10.1364\/OL.32.001495","article-title":"High Efficiency Grating Coupler between Silicon-on-Insulator Waveguides and Perfectly Vertical Optical Fibers","volume":"32","author":"Roelkens","year":"2007","journal-title":"Opt. Lett."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"24433","DOI":"10.1364\/OE.23.024433","article-title":"High-Performance Silicon-on-Insulator Grating Coupler with Completely Vertical Emission","volume":"23","author":"Tseng","year":"2015","journal-title":"Opt. Express"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1366","DOI":"10.1109\/LPT.2003.818246","article-title":"Fast and Low-Power Thermooptic Switch on Thin Silicon-on-Insulator","volume":"15","author":"Espinola","year":"2003","journal-title":"IEEE Photonics Technol. Lett."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"25084","DOI":"10.1364\/OE.23.025084","article-title":"Wavelength Tuning and Stabilization of Microring-Based Filters Using Silicon in-Resonator Photoconductive Heaters","volume":"23","author":"Jayatilleka","year":"2015","journal-title":"Opt. Express"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"22268","DOI":"10.1364\/OE.27.022268","article-title":"Two-Dimensional Silicon Photonic Grating Coupler with Low Polarization-Dependent Loss and High Tolerance","volume":"27","author":"Xue","year":"2019","journal-title":"Opt. Express"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"4001","DOI":"10.1364\/OE.380338","article-title":"Two-Dimensional Grating Coupler on Silicon with a High Coupling Efficiency and a Low Polarization-Dependent Loss","volume":"28","author":"Chen","year":"2020","journal-title":"Opt. Express"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"8400407","DOI":"10.1109\/JQE.2021.3095289","article-title":"High-Efficiency Two-Dimensional Perfectly Vertical Grating Coupler With Ultra-Low Polarization Dependent Loss and Large Fibre Misalignment Tolerance","volume":"57","author":"Zhang","year":"2021","journal-title":"IEEE J. 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