PML Settings for a Photonics Structure


Hello Sir/Ma’am,
I am struck on a problem related to the photonic structure. I am sharing my file which so that you can get my problem. The thing is when I am using “Extended Structure Through PML”, I am getting diverging error. For this problem a link is given on the web so changing the settings that is by unchecking the “extended structure through PML” and then drawing the structure in the PML manually still there is diverging problem.
This is the link of my file. I will be very grateful if you can have a look on it.
As I was having diverging problem even after changing the settings and drawing the PML manually, I just increased the length, width and breadth of Si,Air and SiO2 layer in the PML but without having any hole in the PML boundary and I was able to perform the propagation of mode. By doing this I got some result but there was some reflection.

Please have a look on my file. I will be very thankful to you.
Thanks in Advance


Hi, since it seems that the divergence comes from the PML, I would recommend trying the stabilized profile with higher number of layer to compensate for decreased absorption:


Thank you sir for you kind reply. I have tried my simulation with 64PML layers but even then I was getting diverging problem. Here is my file, it will be great help if you can please go through it. In the file I am attaching the PML layers are selected to be 20 because of less memory to upload.
I am eagerly waiting for your reply.
Thanks in Advance


Hello Sir, by using “Stabilized PML”, will it take more time than the one I was using previously?
This is happening to me as it needs more memory.


Yes, when you increase the number of PML layers, the simulation memory requirements and time will go up. This is one of the trade offs for using Stabilized PML that needs to use more layers to achieve good absorption.