Accurate dipole radiation model for waveguide grating couplers
Accurate dipole radiation model for waveguide grating couplers
An analytical theoretical model for the waveguide grating coupler is developed and applicable to practical deep gratings. The grating-assisted input coupling efficiency is calculated by considering the reciprocal out-coupling problem. The deep grating structure is modelled as an optical layer filled with polarization dipole sources, and the scattered fields are then calculated using the associated Green’s functions and taking into account the multiple reflections and interference from the adjacent layers. The joint loss between the grating region and the waveguide is also considered. Comparison with numerical simulations shows very good agreement and validates the accuracy of the analytical model. The model explicitly describes the importance of multilayer interference of the scattered fields and guided-mode joint loss on the total grating-assisted coupling efficiency and can be used for practical waveguide grating coupler design with negligible computation workload.
Coupling efficiency, Dipole radiation, Guided mode, Multilayer interference, Waveguide grating coupler
Liu, Zhen
ab2e4170-b059-48c1-8ac7-63ee8b8f10b3
Ettabib, Mohamed
71b98cd3-9b2a-4f73-b4c2-0f4b59cacf50
Wilkinson, James S.
73483cf3-d9f2-4688-9b09-1c84257884ca
Zervas, Michael
1840a474-dd50-4a55-ab74-6f086aa3f701
June 2023
Liu, Zhen
ab2e4170-b059-48c1-8ac7-63ee8b8f10b3
Ettabib, Mohamed
71b98cd3-9b2a-4f73-b4c2-0f4b59cacf50
Wilkinson, James S.
73483cf3-d9f2-4688-9b09-1c84257884ca
Zervas, Michael
1840a474-dd50-4a55-ab74-6f086aa3f701
Liu, Zhen, Ettabib, Mohamed, Wilkinson, James S. and Zervas, Michael
(2023)
Accurate dipole radiation model for waveguide grating couplers.
Results in Physics, 49 (6), [106526].
(doi:10.1016/j.rinp.2023.106526).
Abstract
An analytical theoretical model for the waveguide grating coupler is developed and applicable to practical deep gratings. The grating-assisted input coupling efficiency is calculated by considering the reciprocal out-coupling problem. The deep grating structure is modelled as an optical layer filled with polarization dipole sources, and the scattered fields are then calculated using the associated Green’s functions and taking into account the multiple reflections and interference from the adjacent layers. The joint loss between the grating region and the waveguide is also considered. Comparison with numerical simulations shows very good agreement and validates the accuracy of the analytical model. The model explicitly describes the importance of multilayer interference of the scattered fields and guided-mode joint loss on the total grating-assisted coupling efficiency and can be used for practical waveguide grating coupler design with negligible computation workload.
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More information
Accepted/In Press date: 6 May 2023
e-pub ahead of print date: 15 May 2023
Published date: June 2023
Additional Information:
This work was funded by the U.K. Engineering and Physical Sciences Research Council (EPSRC) under Grant EP/ R011230/1, “Flexible Raman biosensing platform for low-cost health diagnostics”. Z.L. acknowledges financial support from the China Scholarship Council (Grant No. 201808430227)
Keywords:
Coupling efficiency, Dipole radiation, Guided mode, Multilayer interference, Waveguide grating coupler
Identifiers
Local EPrints ID: 474950
URI: http://eprints.soton.ac.uk/id/eprint/474950
PURE UUID: e727fdb6-ae42-402f-abb9-a494da78ae7f
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Date deposited: 07 Mar 2023 17:43
Last modified: 06 Jun 2024 01:33
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Author:
Zhen Liu
Author:
Mohamed Ettabib
Author:
Michael Zervas
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