Recovering parity-time symmetry in highly dispersive coupled optical waveguides
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Author(s)
Nguyen, N
Maier, SA
Hong, M
Oulton, RF
Type
Journal Article
Abstract
Coupled photonic systems satisfying parity-time symmetry (PTS) provide
exibility to engineer the ow of light including non-reciprocal propagation, perfect
laser-absorbers, and ultra-fast switching. Achieving the required index pro le for
an optical system with ideal PTS, i.e. n(x) =n(-x)*, has proven to be difficult due to the challenge of controlling gain, loss and material dispersion simultaneously. Consequently, most research has focused on dilute or low gain optical systems where material dispersion is minimal. In this paper, we study a model system of coupled inorganic semiconductor waveguides with potentially high gain (>1,500 cm-1) and dispersion. Our analysis makes use of coupled mode theory's parameters to quantify smooth transitions between PTS phases under imperfect conditions. We find that the detrimental influence of gain-induced dispersion is counteracted and the key features of parity-time symmetric optical systems are recovered by working with non-identical waveguides and bias pumping of the optical waveguides. Our coupled mode theory results show excellent agreement with numerical solutions, proving the robustness of coupled mode theory in describing various degrees of imperfection in systems with PTS.
exibility to engineer the ow of light including non-reciprocal propagation, perfect
laser-absorbers, and ultra-fast switching. Achieving the required index pro le for
an optical system with ideal PTS, i.e. n(x) =n(-x)*, has proven to be difficult due to the challenge of controlling gain, loss and material dispersion simultaneously. Consequently, most research has focused on dilute or low gain optical systems where material dispersion is minimal. In this paper, we study a model system of coupled inorganic semiconductor waveguides with potentially high gain (>1,500 cm-1) and dispersion. Our analysis makes use of coupled mode theory's parameters to quantify smooth transitions between PTS phases under imperfect conditions. We find that the detrimental influence of gain-induced dispersion is counteracted and the key features of parity-time symmetric optical systems are recovered by working with non-identical waveguides and bias pumping of the optical waveguides. Our coupled mode theory results show excellent agreement with numerical solutions, proving the robustness of coupled mode theory in describing various degrees of imperfection in systems with PTS.
Date Issued
2016-12-23
Date Acceptance
2016-11-10
Citation
New Journal of Physics, 2016, 18
ISSN
1367-2630
Publisher
IOP Publishing
Journal / Book Title
New Journal of Physics
Volume
18
Copyright Statement
© 2016 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence.
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Subjects
Science & Technology
Physical Sciences
Physics, Multidisciplinary
Physics
optics
parity-time symmetry
gain induced dispersion
REFRACTIVE-INDEX
MODE THEORY
MICRORESONATORS
LASERS
GAAS
Fluids & Plasmas
02 Physical Sciences
Publication Status
Published
Article Number
125012