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ID 118406
Author
Sonoi, Shuhei Toyohashi University of Technology
Katamawari, Riku Toyohashi University of Technology
Shimokawa, Manami Toyohashi University of Technology
Inaba, Kyosuke Toyohashi University of Technology
Piedra-Lorenzana, Jose A. Toyohashi University of Technology
Hizawa, Takeshi Toyohashi University of Technology
Fujikata, Junichi Photonics Electronics Technology Research Association|Tokushima University Tokushima University Educator and Researcher Directory KAKEN Search Researchers
Ishikawa, Yasuhiko Toyohashi University of Technology
Keywords
Band engineering
germanium
intensity modulation
photodetectors
silicon photonics
Content Type
Journal Article
Description
This study reports the bandgap engineering of a Ge epitaxial layer on Si to tune the operating wavelength of optical intensity modulators and photodetectors in the C (1.530–1.565μm)+L (1.565–1.625 μm) band. A strip structure of elemental Ge is investigated, rather than wider-gap SiGe or narrower-gap GeSn alloy, to achieve the key property of a C band modulation and improved L band detection. By narrowing the strip to the submicron scale, a tensile lattice strain in Ge, induced by a thermal expansion mismatch with Si, is elastically relaxed by an edge-induced relaxation effect. The photoluminescence peak and photodetection spectra show a significant blue shift as the narrowed direct gap of ~0.77 eV is restored to 0.80 eV of unstrained Ge. A standard SiNx external stressor on a narrow Ge strip induces an increased blue shift or an opposite red shift, depending on the stress polarity in SiNx. The results show that it is possible to tune the operating wavelength of modulators and photodetectors of elemental Ge in the C+L band.
Journal Title
IEEE Journal of Quantum Electronics
ISSN
00189197
15581713
NCID
AA00667423
Publisher
IEEE
Volume
58
Issue
5
Start Page
8400209
Published Date
2022-08-31
Rights
© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
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language
eng
TextVersion
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departments
Science and Technology