Learning Forum

[amora]

Hello,

I need to optimize the parameters of a design to attain a maximum transmission at a specific wavelength (not the whole operating wavelength range). Can I do that please or the optimization just maximizes the transmission at the whole operating wavelength range? I didn't find any option at the optimization to select the operating wavelength.

Thanks

[Guilin Sun]

Yes, you can do this. Actually current optimization only targets one single FOM. In the software, you can specify the monitor at the desired wavelength. then pick up its "T" in optimization target:
This is the case when the monitor only records the single-wavelength result. Please try.

[amora]

But can I run over a large operating wavelength and then optimize to achieve high transmission at only one specific wavelength from that range?

[Guilin Sun]

It is ok,if you are only interested in that specific wavelength.
However, if you are only interested in one wavelength, it is not necessary to run over a larger operating wavelength. I believe that wavelength is larger than the start wavelength, so the actual mesh accuracy is higher than the setting for that specific wavelength.
If you are only interested in that specific wavelength, I would suggest to set the source at that wavelength. If you are interested in averaged transmission over a wavelength, you can simply average them in analysis group or in "model" and the result can be optimized.

[amora]

Just for more clarification, I need to optimize the design to have maximum transmission at a single wavelength and minimum transmission elsewhere. Let's say the operating wavelength range is from 5 to 9 micron, I need to have maximum transmission at 8 and minimum transmission at other wavelengths. Can I do that test?

Also, when I pressed right click on the ''Optimization'', I noticed that the results are not stored as shown in the photo. Is that normal please?

Lastly, what is the difference between ''Maximum Generations'' and ''Generation size'' please?

[Guilin Sun]

For the last question, please visit Ansys Insight: Difference between ''Maximum Generations'' and ''Generation size'' in Optimization
We focus on one question one answer in this forum. So if you have other questions other than ONE question in this topic, please write a new post.
It seems you have changed your original thought to "optimize the parameters of a design to attain a maximum transmission at a specific wavelength (not the whole operating wavelength range)". As mentioned before, the built-in POS has a single FOM, eg, a scalar quantity, or one maximum transmission at the specific wavelength, or an average in broadband, or any result that is a single value, not a matrix od dimension larger than 1. When you want "to have maximum transmission at a single wavelength and minimum transmission elsewhere", you have TWO targets, which is beyond the scope of this optimization.
The good news is, you can manage to get it work by defining a proper FOM. for example, you can first get the average transmission at all other wavelength except that specific wavelength, say T_ave; then you have the transmission at the specific wavelength T_singe. you can define your FOM as
FOM=T_singe/T_ave
This is just an illustration to build one SINGLE FOM. I believe that you are capable of defining a better FOM to realize your expectation to to have maximum transmission at a single wavelength and minimum transmission elsewhere. Just try and see how it works.

[amora]

Thanks for your reply.
I didn't change my thoughts, my initial target was maximize transmission at one wavelength and minimize at others because simply the device will work along a wavelength range.
When you say ''you can first get the average transmission at all other wavelength except that specific wavelength, say T_ave; then you have the transmission at the specific wavelength T_singe. you can define your FOM as
FOM=T_singe/T_ave''
do you mean by writing a script in ''Figure of merit script''? I tried to add any conditions but I couldn't. I believe that the only way to specify any conditions is by using a script, is it right?

[Guilin Sun]

Your first post only talked about the maximum.
You can calculate this FOM in "analysis group" or "model". I just call it as FOM, you can call it whatever, but in the optimization, this ratio is the target to optimize (maximize). You may write the script inside the optimization ''Figure of merit script'' but the scrip has limited functionality. In other means not all the scripts work there. Please try in "analysis group" or "model", output the result, and in Optimization, just choose this result to optimize.