High-efficiency broadband grating out-coupler for thick silicon waveguides with a tuned SiGe layer

We design a novel grating out-coupler while maintaining a Gaussian-shaped far-field output. The approach is based on the patterning of a grating in a SiGe layer on the top surface of a 3-μm-thick Si waveguide. The grating aims at coupling the guided signal into a beam vertically out from the surface...

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Main Authors: Muntaha Sidra Tul, Doughan Isaac, Cherchi Matteo, Roussey Matthieu, Aalto Timo
Format: Article
Language:English
Published: EDP Sciences 2025-01-01
Series:Journal of the European Optical Society-Rapid Publications
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Online Access:https://jeos.edpsciences.org/articles/jeos/full_html/2025/02/jeos20250032/jeos20250032.html
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author Muntaha Sidra Tul
Doughan Isaac
Cherchi Matteo
Roussey Matthieu
Aalto Timo
author_facet Muntaha Sidra Tul
Doughan Isaac
Cherchi Matteo
Roussey Matthieu
Aalto Timo
author_sort Muntaha Sidra Tul
collection DOAJ
description We design a novel grating out-coupler while maintaining a Gaussian-shaped far-field output. The approach is based on the patterning of a grating in a SiGe layer on the top surface of a 3-μm-thick Si waveguide. The grating aims at coupling the guided signal into a beam vertically out from the surface of the chip, i.e., out-coupling. The use of a high refractive index alloy, i.e., silicon-germanium, allows a tunability of the effective index of the guided mode and to modify the field distribution enabling a higher efficiency of the grating. It yields a theoretical efficiency of 75% at the central wavelength of 1583 nm. The overall length of this grating coupler is 500 μm, and the output light is detected at 1 μm above the grating. This type of long grating coupler is intended to be eventually used as sensor in LiDAR (Light detection and ranging) applications.
format Article
id doaj-art-c4e73f049fb144f8b2d1c3d00a171a4f
institution Kabale University
issn 1990-2573
language English
publishDate 2025-01-01
publisher EDP Sciences
record_format Article
series Journal of the European Optical Society-Rapid Publications
spelling doaj-art-c4e73f049fb144f8b2d1c3d00a171a4f2025-08-20T03:51:09ZengEDP SciencesJournal of the European Optical Society-Rapid Publications1990-25732025-01-012123410.1051/jeos/2025030jeos20250032High-efficiency broadband grating out-coupler for thick silicon waveguides with a tuned SiGe layerMuntaha Sidra Tul0Doughan Isaac1Cherchi Matteo2Roussey Matthieu3https://orcid.org/0000-0002-7679-6995Aalto Timo4Center for Photonics Sciences, University of Eastern FinlandCenter for Photonics Sciences, University of Eastern FinlandVTT Technical Research Center of FinlandCenter for Photonics Sciences, University of Eastern FinlandVTT Technical Research Center of FinlandWe design a novel grating out-coupler while maintaining a Gaussian-shaped far-field output. The approach is based on the patterning of a grating in a SiGe layer on the top surface of a 3-μm-thick Si waveguide. The grating aims at coupling the guided signal into a beam vertically out from the surface of the chip, i.e., out-coupling. The use of a high refractive index alloy, i.e., silicon-germanium, allows a tunability of the effective index of the guided mode and to modify the field distribution enabling a higher efficiency of the grating. It yields a theoretical efficiency of 75% at the central wavelength of 1583 nm. The overall length of this grating coupler is 500 μm, and the output light is detected at 1 μm above the grating. This type of long grating coupler is intended to be eventually used as sensor in LiDAR (Light detection and ranging) applications.https://jeos.edpsciences.org/articles/jeos/full_html/2025/02/jeos20250032/jeos20250032.htmlsilicon germaniumgrating out-couplerlong devicebroad-bandlidar applications
spellingShingle Muntaha Sidra Tul
Doughan Isaac
Cherchi Matteo
Roussey Matthieu
Aalto Timo
High-efficiency broadband grating out-coupler for thick silicon waveguides with a tuned SiGe layer
Journal of the European Optical Society-Rapid Publications
silicon germanium
grating out-coupler
long device
broad-band
lidar applications
title High-efficiency broadband grating out-coupler for thick silicon waveguides with a tuned SiGe layer
title_full High-efficiency broadband grating out-coupler for thick silicon waveguides with a tuned SiGe layer
title_fullStr High-efficiency broadband grating out-coupler for thick silicon waveguides with a tuned SiGe layer
title_full_unstemmed High-efficiency broadband grating out-coupler for thick silicon waveguides with a tuned SiGe layer
title_short High-efficiency broadband grating out-coupler for thick silicon waveguides with a tuned SiGe layer
title_sort high efficiency broadband grating out coupler for thick silicon waveguides with a tuned sige layer
topic silicon germanium
grating out-coupler
long device
broad-band
lidar applications
url https://jeos.edpsciences.org/articles/jeos/full_html/2025/02/jeos20250032/jeos20250032.html
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AT cherchimatteo highefficiencybroadbandgratingoutcouplerforthicksiliconwaveguideswithatunedsigelayer
AT rousseymatthieu highefficiencybroadbandgratingoutcouplerforthicksiliconwaveguideswithatunedsigelayer
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