Robust optimization of adiabatic tapers for coupling to slow-light photonic-crystal waveguides
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Joannopoulos_Robust optimization.pdf
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Author(s)
Oskooi, Ardavan
Mutapcic, Almir
Noda, Susumu
Boyd, Stephen P.
Joannopoulos, John
Johnson, Steven G
Date Issued
September 2012
Journal
Optics Express
Publisher
Optical Society of America
Citation
Oskooi, Ardavan et al. “Robust Optimization of Adiabatic Tapers for Coupling to Slow-light Photonic-crystal Waveguides.” Optics Express 20.19 (2012): 21558. © 2012 OSA
Version
Final published version
Abstract
We investigate the design of taper structures for coupling to slow-light modes of various photonic-crystal waveguides while taking into account parameter uncertainties inherent in practical fabrication. Our short-length (11 periods) robust tapers designed for λ = 1.55μm and a slow-light group velocity of c/34 have a total loss of < 20dB even in the presence of nanometer-scale surface roughness, which outperform the corresponding non-robust designs by an order of magnitude. We discover a posteriori that the robust designs have smooth profiles that can be parameterized by a few-term (intrinsically smooth) sine series which helps the optimization to further boost the performance slightly. We ground these numerical results in an analytical foundation by deriving the scaling relationships between taper length, taper smoothness, and group velocity with the help of an exact equivalence with Fourier analysis.
MIT Department
Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies
Massachusetts Institute of Technology. Department of Mathematics
Massachusetts Institute of Technology. Department of Physics
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1364/OE.20.021558
