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Global evaluation of ewbe.beta_1 gives same value for all rows (solutions).

Posted Sep 4, 2014, 8:29 a.m. EDT Version 4.4 3 Replies

Micke Malmström
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I've solved the boundary mode analysis for port 1 like in the "Directional Coupler" model but with the addition of two parametric sweeps (wavelength and dimension).

Now I want to extract the effective mode index for all solutions, so I try making a Global Evaluation but the parameter ewbe.neff (or similar) does not exist as I was hoping so I figured that I could calculate it from ewbe.beta_1/(2*pi/wl) where "wl" is the wavelength parameter. However, the values are the same for each row (or solution) part of the table is shown below:

dimension, wl, solution 1, soution 2...
1.5e-6, 1e-6, 2.21885, 2.21885
1.5e-6, 1.64286e-6, 1.92064, 1.92064
1.5e-6, 2.28571e-6, 1.49211+1.64531e-10i, 1.49211+1.64531e-10i


It seems "ewbe.beta_1" is not updated for each solution of the parametric sweep but only for the different values of dimension and wl in the parametric sweeps.

Maybe there is an even easier way of getting the neff for each solution.
3 Replies Last Post Sep 9, 2014, 3:42 p.m. EDT
Micke Malmström
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Posted: 1 decade ago Sep 4, 2014, 8:43 a.m. EDT
If I ask for "Data only" and the first "width"-value, and first "wl"-value it looks like this:

width wl lambda Propagation constant (rad/m)
1.5e-6 1e-6 2.21885 1.39414e7
1.5e-6 1e-6 2.2194 1.39414e7
1.5e-6 1e-6 2.28034 1.39414e7
1.5e-6 1e-6 2.28183 1.39414e7
1.5e-6 1e-6 2.28997 1.39414e7
1.5e-6 1e-6 2.29179 1.39414e7
1.5e-6 1e-6 2.35067 1.39414e7
1.5e-6 1e-6 2.35075 1.39414e7

here lambda is the neff I'm looking for but the "Propagation constant" is the same for all rows. If I choose "All" "width"-values lambda changes to numeric! like this:

width wl lambda Propagation constant (rad/m)
1.5e-6 1e-6 1 1.39414e7
1.5e-6 1e-6 2 1.39414e7
1.5e-6 1e-6 3 1.39414e7
1.5e-6 1e-6 4 1.39414e7
1.5e-6 1e-6 5 1.39414e7
1.5e-6 1e-6 6 1.39414e7
1.5e-6 1e-6 7 1.39414e7
1.5e-6 1e-6 8 1.39414e7
1.94737e-6 1e-6 1 1.43785e7
1.94737e-6 1e-6 2 1.43785e7
...
...
If I ask for "Data only" and the first "width"-value, and first "wl"-value it looks like this: width wl lambda Propagation constant (rad/m) 1.5e-6 1e-6 2.21885 1.39414e7 1.5e-6 1e-6 2.2194 1.39414e7 1.5e-6 1e-6 2.28034 1.39414e7 1.5e-6 1e-6 2.28183 1.39414e7 1.5e-6 1e-6 2.28997 1.39414e7 1.5e-6 1e-6 2.29179 1.39414e7 1.5e-6 1e-6 2.35067 1.39414e7 1.5e-6 1e-6 2.35075 1.39414e7 here lambda is the neff I'm looking for but the "Propagation constant" is the same for all rows. If I choose "All" "width"-values lambda changes to numeric! like this: width wl lambda Propagation constant (rad/m) 1.5e-6 1e-6 1 1.39414e7 1.5e-6 1e-6 2 1.39414e7 1.5e-6 1e-6 3 1.39414e7 1.5e-6 1e-6 4 1.39414e7 1.5e-6 1e-6 5 1.39414e7 1.5e-6 1e-6 6 1.39414e7 1.5e-6 1e-6 7 1.39414e7 1.5e-6 1e-6 8 1.39414e7 1.94737e-6 1e-6 1 1.43785e7 1.94737e-6 1e-6 2 1.43785e7 ... ...
Micke Malmström
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Posted: 1 decade ago Sep 5, 2014, 9:52 a.m. EDT
One workaround was to make a 2D Mode analysis with the emw package. and get emw.neff directly...
One workaround was to make a 2D Mode analysis with the emw package. and get emw.neff directly...
Micke Malmström
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Posted: 1 decade ago Sep 9, 2014, 3:42 p.m. EDT
FYI ewbe.beta_1 will always give the first mode index "found" no matter what parametrizations is done...
FYI ewbe.beta_1 will always give the first mode index "found" no matter what parametrizations is done...

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