Asymmetric Light Transmission in PT-Symmetric Microring Resonators

We propose a new type of add-drop microring resonator made of gain and loss materials. Microring resonators are compact, narrow band, and optical channel dropping filters. In such linear systems, light transmission to side-coupled signal waveguides is always symmetric. However, we prove that properl...

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Bibliographic Details
Published in:IEEE journal of selected topics in quantum electronics 2016-09, Vol.22 (5), p.19-24
Main Authors: Giden, Ibrahim Halil, Dadashi, Khalil, Botey, Muriel, Herrero, Ramon, Staliunas, Kestutis, Kurt, Hamza
Format: Article
Language:English
Subjects:
Fotònica
Física
Microphotonics
Modulation
Optical filters
Optical ring resonators
optical systems
Optical waveguides
parity-time symmetry
photonic devices
Photonics
Power generation
Refractive index
resonators
Àrees temàtiques de la UPC
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Summary:We propose a new type of add-drop microring resonator made of gain and loss materials. Microring resonators are compact, narrow band, and optical channel dropping filters. In such linear systems, light transmission to side-coupled signal waveguides is always symmetric. However, we prove that properly arranging a gain and loss modulation in the microring resonator provides a new functionality: asymmetric transmission; so that different resonant modes can be promoted depending on the input channel. This can be achieved when the resonator holds parity-time (PT-) symmetry, with periodic gain-loss and index modulations. PT-symmetry in optics generally requires that the index and gain-loss modulations are dephased by a quarter of the wavenumber of the modulation. Besides, we show that a simple half-gain half-loss microring also produces analogous results to a periodic PT-symmetric system. The results are numerically proved and also accounted by a simple analytical model. The effect of using complex modulated resonators with smaller periodicities is also analyzed.
ISSN:1077-260X
1558-4542
DOI:10.1109/JSTQE.2016.2542782