Hi Guys!
I have a structure just like this;
l l
l l
l l 0.1
l l___ :
l ___I 0.2 Y
l l : :
l l :
l l :
l -0.5- l X............:
I am trying to measure the reflection and the transmission inside the
straight waveguide. I run the simulation twice. In the firs run the
structure is just the straight waveguide (width= 0.5 micrometer) and the
second run I have a grating with size of height =0.1 and width=0.2 um.
I use the code below but I had transmission > 1.
Please give me a hand.
I am keen to hear any suggestion.
Thanks a lot in advance.
(set-param! resolution 50.000000 )
(set! geometry-lattice (make lattice (size 10.95 10.3 1.04)))
(define-param No-Grating? false) ; if true, have straight waveguide without
grating on top
(set! geometry
(if No-Grating?
(list
(make block ( center 0 0 0.4) ( size 10.95 10.3 1.02 ) (material (make
dielectric (epsilon 1))))
(make block ( center 0 0 -0.51) ( size 10.95 10.3 0.8 ) (material (make
dielectric (epsilon 2.3104))))
(make block ( center -4.225 0 0) ( size 0.5 10.3 0.22 ) (material
(make dielectric (epsilon 12.0409)))))
(list
(make block ( center 0 0 0.4) ( size 10.95 10.3 1.02 ) (material (make
dielectric (epsilon 1))))
(make block ( center 0 0 -0.51) ( size 10.95 10.3 0.8 ) (material (make
dielectric (epsilon 2.3104))))
(make block ( center -4.225 0 0) ( size 0.5 10.3 0.22 ) (material
(make dielectric (epsilon 12.0409))))
(make block ( center -3.925 0 0) ( size 0.1 0.2 0.22 ) (material
(make dielectric (epsilon 12.0409))))
)))
(set! sources (list
(make source
(src (make gaussian-src (frequency 0.64516129) (fwidth 0.8377272)))
(component Ex)
(center -4.225 -4.7 0)
(size 0.5 0 0.22))))
;boundaries specification
(set! pml-layers
(list
(make pml (direction X) (side Low) (thickness 0.4))
(make pml (direction Y) (side Low) (thickness 0.4))
(make pml (direction Z) (side Low) (thickness 0.4))
(make pml (direction X) (side High) (thickness 0.4))
(make pml (direction Y) (side High) (thickness 0.4))
(make pml (direction Z) (side High) (thickness 0.4))
))
(define-param fcen 0.64516129) ; pulse center frequency
(define-param df 0.8377272) ; pulse width (in frequency)
(define-param nfreq 100) ; number of frequencies at which to compute flux
(define trans ; transmitted flux
(add-flux fcen df nfreq
(if No-Grating?
(make flux-region
(center -4.225 4.5 0) (size 1 0 0.44))
(make flux-region
(center -4.225 4.5 0) (size 1 0 0.44)))))
(define refl ; reflected flux
(add-flux fcen df nfreq
(make flux-region
(center -4.225 -4.5 0) (size 1 0 0.44))))
(if (not No-Grating?) (load-minus-flux "refl-flux" refl))
(run-sources+ 100 (at-beginning output-epsilon))
(if No-Grating? (save-flux "refl-flux" refl))
(run-sources+
(stop-when-fields-decayed 50 Ex
(if No-Grating?
(vector3 -4.225 4.5 0)
(vector3 -4.225 4.5 0))
1e-3))
(display-fluxes trans refl)
--
*PhD Std. Kenan CICEK*
*Faculty of Engineering Queen's Building room 2.8 *
*University of Bristol *
*Bristol BS8 1TR, UK*
*Tel (+44) 0117 331 5456*
* E-mail: ee...@bristol.ac.uk*
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