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Interaction Between Two One-Way Waveguides
Zhejiang University, China.
Zhejiang University, China.
2012 (English)In: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 48, no 8, 1059-1064 p.Article in journal (Refereed) Published
Abstract [en]

The interaction between two (parallel) one-way waveguidesformed by photonic crystals is investigated theoretically. It is shown that when thetwo waveguides support modes propagating in opposite directions, they can effectively interact with each other only within a narrow guiding region where their propagation constants are nearly zero. In this coupling window, the waveguides are contra-directionally coupled and the efficiency grows monotonously with the coupling length, reaching 100% as the coupling length is large enough. When the one-waywaveguides support the modes propagating in the same direction, they may be efficiently coupled through the whole guiding regime, and their coupling exhibits the same behavior as the conventional uniform waveguides. The coupling between theone-way waveguides is first analyzed with the coupled-mode approximation and then verified by rigorous numerical simulation. 

Place, publisher, year, edition, pages
IEEE , 2012. Vol. 48, no 8, 1059-1064 p.
Keyword [en]
coupling, nonreciprocity, one-way waveguides, photonic crystals
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
URN: urn:nbn:se:kth:diva-190012DOI: 10.1109/JQE.2012.2202215ISI: 000305572600001ScopusID: 2-s2.0-84862565201OAI: oai:DiVA.org:kth-190012DiVA: diva2:950370
Note

QC 20160815

Available from: 2016-07-29 Created: 2016-07-29 Last updated: 2016-08-16Bibliographically approved
In thesis
1. Theoretical Investigation on Propagation and Coupling of Nonreciprocal Electromagnetic Surface Waves
Open this publication in new window or tab >>Theoretical Investigation on Propagation and Coupling of Nonreciprocal Electromagnetic Surface Waves
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis aims at revealing the fundamental guiding and coupling properties of nonreciprocal electromagnetic surface waves on magneto-optical or gyromagnetic media and designing novel applications based on the properties.

We introduce the background in the first chapter. We then describe the concept of nonreciprocity and the main calculation method in the second chapter. In the third chapter, we show that one-way waves can be sustained at the edge of a gyromagnetic photonic crystal slab under an external magnetic field. We also investigate the coupling between two parallel one-way waveguides. We reveal the condition for effective co-directional and contra-directional coupling. We also notice that the contra-directional coupling is related to the concept of a “trapped rainbow”.

In the fourth chapter, we address the concept of a “trapped rainbow”. It aims at trapping different frequency components of the electromagnetic wave packet at different positions in space permanently. In previous structures, the entire incident wave is reflected due to the strong contra-directional coupling between forward and backward modes. To overcome this difficulty, we show that utilizing nonreciprocal waveguides under a tapered external magnetic field can achieve a truly “trapped rainbow” effect at microwave frequencies. We observe hot spots and relatively long duration times around critical positions through simulations and find that such a trapping effect is robust against disorders.

Lastly, in the fifth chapter, we study the one-way waves in a surface magnetoplasmon cavity. We find that the external magnetic field can separate the clockwise and anti-clockwise cavity modes into two totally different frequency ranges. This offers us more choices, both in the frequency ranges and in the one-way directions, for realizing one-way components. We also show the waveguide-cavity coupling by designing a circulator, which establishes the foundation for potential applications.

Place, publisher, year, edition, pages
KTH Royal Institute of Technology, 2016. xii, 62 p.
Series
TRITA-EE, ISSN 1653-5146 ; 2016:094
Keyword
wave propagation, coupling, magneto-optical, gyromagnetic, photonic crystal, nonreciprocity, one-way, trapped rainbow
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-190792 (URN)978-91-7729-055-1 (ISBN)
Public defence
2016-09-09, F3, Lindstedtsvägen 26, Stockholm, 10:00 (English)
Opponent
Supervisors
Funder
Swedish Research Council, VR 621-2011-4620
Note

QC 20160816

Available from: 2016-08-16 Created: 2016-08-15 Last updated: 2016-08-16Bibliographically approved

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