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Scaling law, confined and surface modes in photonic fibonacci stub structures: theory and experiment

Authors :
Bahram Djafari-Rouhani
N. Ouchani
H. Aynaou
A. Mouadili
Abdellatif Akjouj
E. H. El Boudouti
École Nationale d’Ingénieurs de Monastir (ENIM)
LPMR, Department de Physique, Faculty of science, University Mohammed I
Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN)
Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)
Physique-IEMN (PHYSIQUE-IEMN)
Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)
Université de Monastir - University of Monastir (UM)
Université Hassan II [Casablanca] (UH2MC)
Université Mohammed Premier [Oujda]
Physique - IEMN (PHYSIQUE - IEMN)
Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA)
Université catholique de Lille (UCL)-Université catholique de Lille (UCL)-Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA)
Université catholique de Lille (UCL)-Université catholique de Lille (UCL)
This research received no external funding.
Source :
Applied Sciences-Basel, Applied Sciences-Basel, 2020, 10 (21), 7767, 24 p. ⟨10.3390/app10217767⟩, Applied Sciences, Volume 10, Issue 21, Applied Sciences, 2020, 10 (21), pp.7767. ⟨10.3390/app10217767⟩, Applied Sciences, Vol 10, Iss 7767, p 7767 (2020)
Publication Year :
2020
Publisher :
HAL CCSD, 2020.

Abstract

We investigate both theoretically and experimentally the properties of electromagnetic waves propagation and localization in periodic and quasi-periodic stub structures of Fibonacci type. Each block constituting the Fibonacci sequence (FS) is composed of an horizontal segment and a vertical stub. The origin of the primary and secondary gaps shown in such systems is discussed. The behaviors and scattering properties of the electromagnetic modes are studied in two geometries, when the FS is inserted horizontally between two semi-infinite waveguides or grafted vertically along a guide. Typical properties of the Fibonacci systems such as the fragmentation of the frequency spectrum, the self-similarity following a scaling law are analyzed and discussed. It is found that certain modes inside these two geometries decrease according to a power law rather than an exponential law and the localization of these modes displays the property of self-similarity around the central gap frequency of the periodic structure where the quasi-periodicity is most effective. Also, the eigenmodes of the FS of different generation order are studied depending on the boundary conditions imposed on its extremities. It is shown that both geometries provide complementary information on the localization of the different modes inside the FS. In particular, in addition to bulk modes, some localized modes induced by both extremities of the system exhibit different behaviors depending on which surface they are localized. The theory is carried out using the Green&rsquo<br />s function approach through an analysis of the dispersion relation, transmission coefficient and electric field distribution through such finite structures. The theoretical findings are in good agreement with the experimental results performed by measuring in the radio-frequency range the transmission along a waveguide in which the FS is inserted horizontally or grafted vertically.

Details

Language :
English
ISSN :
20763417
Database :
OpenAIRE
Journal :
Applied Sciences-Basel, Applied Sciences-Basel, 2020, 10 (21), 7767, 24 p. ⟨10.3390/app10217767⟩, Applied Sciences, Volume 10, Issue 21, Applied Sciences, 2020, 10 (21), pp.7767. ⟨10.3390/app10217767⟩, Applied Sciences, Vol 10, Iss 7767, p 7767 (2020)
Accession number :
edsair.doi.dedup.....ebc013f7c6b7013774e8f182cca5068c
Full Text :
https://doi.org/10.3390/app10217767⟩