On 06/26/2017 03:37 PM, Julián Leonel Pita Ruiz wrote:
I was testing the eigenmode source function on meep and I think I
encountered an error.
I use a simple strip waveguide centered at the computational domain and
the obtained results seem correct. When I included an spatial offset
(that is, the waveguide is not centered), however, the calculated
effective index and feeding mode profile do not correspond to those of
the fundamental mode.
Has anyone observed this issue?
I wasn't able to reproduce your error. The example works fine for me.
MPB computes the same mode in both cases and the eigenmode source
produces identical fields in the waveguide.
To verify this, I added the following run function to the end of your
script:
(run-sources+ (stop-when-fields-decayed 50 Ez (vector3 source-x source-y
source-z) 1e-6)
(in-volume (volume (center 0 0 0) (size 0 LY LZ))
(at-beginning output-epsilon) (at-every 25 output-efield)))
I ran two sets of tests with guide-z=0 and 1. Then, in post processing
via the shell, I generated field images for the 3 components at the
waveguide cross section where the source is located using h5topng of
h5utils, e.g.:
for i in {x,y,z}; do h5topng -C eig-src-eps-000000.00.h5 -o
guidez1-t100-e${i}.png -vZc bluered -d e${i} eig-src-e-000100.00.h5; done
The individual field components for the two waveguide/source locations
are identical at the same time instance.
Also, note that you can use two mirror symmetry planes (Y and Z) in this
example to reduce the computation size by a factor of 4.
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