Hi all Meep users,
I am trying to get the drop port spectrum of a microring filter. The first
problem is that the result seems to be wrong since the spectrum I got is not
realistic. The second problem is the Gaussian source. I tried a continuous
source before which is not suitable for this simulation. Then I use a Gaussian
source to see what happens. But in the output GIF image, the Gaussian source
works the same as the continuous source. I even can't use "stop-when
fields-decayed" to finalize the simulation because the Gaussian source works
like a continuous source and the power is stable. Can anyone help me?
(define-param n 3.4) ;index ofwaveguide
(define-param fcen .645) ; frequency of source
(define-param L 20.94) ; holds distance
(define-param gap .0415) ; gap is 41.5nm
(define-param fspread .2) ; spread in gaussian freq range
(define-param nfreq 100) ; number of frequencies at which to compute flux
(define-param rho 3.3346) ; radius of circles in track
(define-param gap_wg .17) ; this is the gap between ring and waveguide
(define-param gap2_wg .1) ; this is the gap between ring and waveguide
(define-param gap_index .035) ; this is the gap bw index modulator and ring
(define-param guide_z .2)
(define-param guide_r .2) ;this is the radial thickness of ring
(define-param size_z 2)
(define-param size_x 10)
(define-param size_y 10)
(define-param pml_thickness 2)
(set! geometry-lattice (make lattice (size 30 12)))
(set! geometry
(list
(make cylinder (center 0 0) (height infinity)
(radius rho) (material (make dielectric (epsilon 11.7))))
(make cylinder (center 0 0) (height infinity)
(radius (- rho guide_r)) (material air))
(make block (center 0 (+ rho guide_r gap_wg)) (size 60 guide_r
infinity)
(material (make dielectric (epsilon 11.7))))
(make block (center 0 (- (+ rho guide_r gap2_wg))) (size 60 guide_r
infinity)
(material (make dielectric (epsilon 11.7))))
))
(set! sources (list
(make source
(src (make continuous-src (frequency fcen) (fwidth fspread)))
(component Ez)
(center -14 (+ rho guide_r gap_wg) )
)))
(define trans ; transmitted flux
(add-flux fcen fspread nfreq
(make flux-region
(center -14 (- (+ rho guide_r gap2_wg))) (size 0 (* guide_r
2)))))
(set! pml-layers (list (make pml (thickness 1))))
(set! resolution 20)
(use-output-directory)
(run-until 500
(at-beginning output-epsilon)
(to-appended "ez" (at-every 1 output-efield-z)))
(display-fluxes trans) ; print out the flux spectrum
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