Importing and exporting GDSII files

Import: The GDSII import simulation object allows you to import structures from a GDSII file into the layout editor. The GDSII file format is commonly used to store 2-dimensional geometric data. This data can be directly imported into a 2D layout environment, or it can be used to import 3D objects into a 3D layout environment by extruding the 2D data in the Z dimension.

Export: An example can be found on the GDSII export automation and GDSII real example page. Users may also find the built-in Layer builder function useful when importing and exporting GDS files.

Characteristics of the GDSII file

Lumerical products support most, but not all features of the GDSII file format. Unsupported features should not prevent the file from being imported, however, the results may not be as expected. The following table details the supported and unsupported features.

Note: Path corners

Path objects in GDSII files are piecewise linear lines plus a width and optionally some information on how to handle corners and ends. In general, GDSII files support several types of corner style options (squared, rounded, extended squared, etc). Our import function supports type 0 (squared ends flush to the end-point) and will default to type 2 (square ends with 1/2 the width added to the end-point) for all other types.

Note: Flattened GDSII files

While we do include scale, rotate, flip, and automatic flattening of references, not all features of GDSII are currently supported. If you run into any problems, you may have better results by flattening the file first.

GDSII file import

Import using GUI

GDSII import is initiated by accessing the IMPORT->GDSII option from the FILE menu, or by pressing the Import GDS button located on the main toolbar. This will bring up a standard file browser, which will allow you to select a file with the extension .gds or .db. Selecting a GDSII file will bring up the Single layer GDSII Import window as shown below. A downloadable associated file GDS_export.gds can be used to test the GUI import function.

The following 3 input parameters control how the GDSII data is imported:

• Cell name: This selection menu contains the valid cells available in the GDSII library. Select the cell you wish to import.
• Layer number: This selection menu contains all of the layer number present in the GDSII file. Only structures with the selected layer number will be imported by this operation.
• Material: This selection menu contains a list of the valid materials in your current simulation environment. This material will be assigned to the imported structures.

Selecting the Import layer button imports all the structures with the selected layer number in the selected cell into the layout environment. These structures are automatically inserted into a structure group. The material is set as an input parameter for the structure code, and the script in the structure group sets all the objects to the desired material. The name of the structure group includes the original number of layers. For 3D simulations, the structure group contains a variable "z span". This used to set the width of the layer in the z direction. The origin of the structures, as well as their orientation, can be changed by changing the properties of the structure group.

In the simple ' GDS_export.gds ' example file, valid cell/layer combinations with structure information are:

Substrate / Layer 1

Si_polygon / Layer 2

Au_particle / Layer 3

Au_particle_array / Layer 3

Import using script command

The GDSII file can also be imported via script, the command gdsimport can be used, see stage 3 of the associated files GDS_export_import.lsf for example. For more information of the script commands, please visit List of commands .

GDSII file export

To export a graphical design to .gds format, the following commands can be used, see stage 2 of the associated file GDS_export_import.lsf for example.

gdsopen, gdsclose, gdsbegincell, gdsendcell, gdsaddcircle, gdsaddpoly, gdsaddrect, gdsaddref

The graphical information can be exported to the a .gds file in the current working directory. For more information of the commands, please visit Reference Guide - List of commands.

To automate the GDSII file export process, please visit the KB page GDSII export automation and GDSII real example

See also

List of commands script commands

Layer builder

GDSII export automation and GDSII real example