Thermally tuned waveguide (FDE)

talimutalimu Member Posts: 8
edited March 31 in Photonics

Hi Support team,

In your example "Thermally tuned waveguide (FDE)", you use "sweep" in order to sweep the input power from 20 to 30mW as shown here:

Each file "ldev" of this sweep is resored in a subdirectory "thermal_tuning_waveguide_2D_sweep".

In addition, T.mat file is created in the same subdirectory:

1) What is this file ? Does it being creat automatically along with "sweep"?

2) What are the temperature values in this file? why 48 values (see bellow)?

3) How is named "T" ?

Thanks,

Tali M.

Comments

  • talimutalimu Posts: 28Member

    Hi,

    Appreciate your reply.

    Thanks in Advance,

    talimu 

  • GWANGGWANG Posts: 81Ansys Employee

    Hi talimu,


    Thank you for your patience and sorry for the late reply. Regarding your questions:

    1. This file is not created by the sweep but by the thermal monitor "wg_monitor". When you edit the monitor, there is a file save option and it will save a mat file to the current running directory. There is only one of this file generated because when running the sweep, the later generated T.mat file will overwrite the previous generated one.
    2. The temperature dimension is due to the mesh size in the monitor.
    3. Same as in point 1, the file is defined as name "T.mat", you can rename it.
  • talimutalimu Posts: 28Member

    Hi GWANG,

    Thank you for reply.

    Regarding your reply 2) above: 1)  If 48 is mesh size, why the size of “elements” is 76X3 ?

    Thanks,

    Tali M.

  • talimutalimu Posts: 28Member

    Hi  GWANG,

    Will appreciate your reply. I uploaded it prior to website upgrade.

    Thanks,

    talimu

  • GWANGGWANG Posts: 81Ansys Employee

    Hi talimu,


    That's because the monitor "T" and the elements have different range. The mesh sizes are the same, though the monitor "T" has a smaller area, so it occupies 48 meshes size.

    Hope this is clear.

  • talimutalimu Posts: 28Member
    edited April 22

    Hi GWANG,

    Thank you for your reply.

    1) Both of them are produced from the same area of "wg_monitor_1",so why they have different ranges?

    2) Later on in this example, you use "element" in the script file the following, So, why use here "elements" and the size of "T" array?


    Thanks,

    Tali M.

  • talimutalimu Posts: 28Member

    Hi GWANG,

    Following my question above regarding "element" in the script  file (would appreciate your reply on it),

    1) Can you please explain why do we need to prepare an empty array called perturbation (marked in red below), what "elements" represent in this empty array?

    2) Later on "index " is added to "perturbation" as an attribute (see marked in blue above).

    Please explain how "element" connected to "index in perturbation array.


    Thanks in Advance,

    talimu

  • kghaffarikghaffari Posts: 45Ansys Employee

    Hi Talimu,

    Responding to your first two questions:

    1 – In finite elements given that the data is unstructured, in addition to the coordinates (x, y, z) a connectivity matrix (elements) is needed to clarify the connections. For the elements matrix, the number of rows will be equal to the number of shapes in the mesh (here 76). X, y, and z will be the coordinates of the points where the mesh cells meet each other (here 48). So the two numbers don’t necessarily match. More information about unstructured data set can be found in this article.

    2 – As mentioned above creating the unstructured data set requires the connectivity matrix (in addition to the coordinates). The line highlighted in the code corresponds to the syntax required for the unstructureddataset command.

  • kghaffarikghaffari Posts: 45Ansys Employee

    Regarding the next two questions:

    1 – The array is prepared to store the calculated perturbation data at each location. The positions correspond to the temperatures obtained earlier, so the matrix is created using the same coordinates. Again, elements will connect the coordinates to each other.

    2- Here the size of index will match the created dataset, because the derivation is based on T. Here, elements has already been used to create the array.

    Kind regards,

    Khashayar

  • talimutalimu Posts: 28Member

    Hi Khashayar,

    Thank you for your reply,

    I have some questions:

    As we already know, T.mat file is produced, using “thermal_tuning_waveguide_2D.idev”. Then it is imported into “thermal_tuning_waveguide_2D.ims”, to find modes.

    1)     Can you explain why x span and y span marked in red below ( temperatureGridAttribute menu in .ims file) don’t match the dimension of the wg_monitor from the former file (.idev file) we import the T.mat

    file from? x span and y span are smaller than "wg_monitor" dimension. what are these values represent?


    2)     Why the temperatureGridAttribute area (in purple above) is not located symmetrically around wg? Is it important for calculation? Because I think that when it is located like that, it’s not represent well the

    temperature mapping extracted of the original structure.

    3)     What are the thin purple lines (marked in yellow arrow above) within temperatureGridAttribute area?

    Thanks,

    Talimu

  • kghaffarikghaffari Posts: 45Ansys Employee
    edited May 21

    Hi,

    1 – The .mat consists of the data exported from the other monitor “wg_monitor_1”. You can trace the exported data back in the parameter sweep. The x and y span are larger than the size of this monitor

    2 – The monitor in CHARGE that the data is exported from, matches the shape of the waveguide and has a rectangular shape. However, given that the mesh is triangular, some of the cells extend beyond the boundaries and additional data corresponding to outer regions are also obtained:

    This is reflected in the bigger geometry of the temperature grid as well. All of the area of interest is covered plus some extra regions.

    3 – These represent the original finite element mesh created in CHARGE.

    Best,

    Khashayar

  • talimutalimu Posts: 28Member

    Thank you, Khashayar

  • yangxiaofeiyangxiaofei Posts: 1Member

    Hi Support team, Can you please explain why only the t T.mat is imported to the MODE and only show two values ( T_sub_index,T_sub).


  • kghaffarikghaffari Posts: 45Ansys Employee

    Hi, I suspect you might have missed the step in the example where the following code is run to save the results of the sweep:

    T=getsweepresult("sweep","T");
    matlabsave("T.mat",T);
    

    This will update the file and allow you to see the additional parameters P_index and P which will enable the script to indicate the power of interest when calculating the optical properties.

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