Help with Exporting To GDS - Lumerical Grating Coupler Example

graemebargengraemebargen Member Posts: 5


I have run through the entire example of the inverse design of grating coupler 2D from

I have modified the parameters for my own use. I have modified the model to create a fully etched geometry (the grating etches in the silicon device layer are the entire height of the layer, in this case 600nm). However when I export the design to GDS it does not create the proper GDS geometry in that it is not fully etched (eg. the etches should be empty space, not a polygon) as you can see from the screenshot below:

The etched regions seem to be being treated the same as the full height silicon device layer. I am not overly familiar with the GDS export fucntion, but in the example code given in the file from the link above the following code is given:

Can anyone help me how I can amend the code to create the proper GDS file for the fully etched gratings?


  • trobertstroberts Posts: 37Ansys Employee


    So GDS has no concept of thickness, and the gds script here exports both etched and unetched layer as two layers. Depending on what type of resist you are using in your process (positive/negative) then you could imagine building the mask using either of these layers.

    These layers are defined via layer_def argument. Simply delete the second layer definition if you don't want to include this in your gds export.

    "layer_def =  [1, 0.0, {0}];".format(height) 


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