S-parameter (Fixed) data collection wizard

The fixed S-parameter model data collection wizard allows you to automatically generate s-parameter compact models using Ansys Lumerical CML Compiler™ based on the spar_fixed photonic model, using simulation files from either Ansys Lumerical FDTD™ or Ansys Lumerical MODE™.

Required licenses

Ansys Lumerical MODE™ GUI license (For MODE input files)
Ansys Lumerical FDTD™ GUI license (For FDTD input files)
Ansys Lumerical CML Compiler license (For direct export of compiled INTERCONNECT models)

Preparing simulation files

The input can either be a FDTD project file (.fsp), or a MODE project file (.lms). The simulation files must meet the following requirements:

An s-parameter sweep with the FDTD solver in FDTD, or the EME solver in MODE must be successfully completed. You must set up the export tab to your preference prior to running the data collection wizard.

Starting the wizard

The S-parameter (fixed) data collection wizard package files are attached to this article. The attached files include the main wizard package as well as packages containing examples. Important files are as follows:

Configuration file: The JSON file in the wizard zip file /wizard/spar_fixed_wizard/gui_config.json contains default configuration for this wizard. Ensure that the lumapi_path variable points to the lumapi.py file included with Lumerical products. You can find the default paths here.
Wizard scripts: The folder /wizard/ within the wizard zip file contains all necessary files to run this tool. You can start the wizard by running the python script named main.py under /wizard/spar_fixed_wizard.
Examples: Several example input files are available in the example zip file.

Wizard interface

Model settings

The first page of the wizard contains general settings for the generation of the fixed s-parameter compact model.

Element Info: Enter the description, prefix, and any notes for the model in this section. You can add multiple notes using the “Add Note” and “Delete Note” buttons.

QA: Configure the wavelength range used for the fixed s-parameter quality assurance test.

Simulation File: Choose the FDTD (.fsp) or MODE (.lms) simulation file the wizard will use and enter the name of the s-parameter sweep in the “S Parameter Sweep Name” field.

After configuring model data, press “Next” to extract s-parameter information from the simulation file and proceed on setting up the ports and output for the model.

Output settings

The second page of the wizard contains confirmation of model information and output settings for the model.

Element information: The scrollable top section of the window contains model information:

The “General Information” subsection displays description and notes you inputted on the previous page.
The “Port” subsection displays the port information from the export settings in the s-parameter sweep object. You have the option to modify some of the port properties using the editable fields within in the window.
The “Simulation Settings” subsection displays wavelength, mode, and group delay information. The wavelength range and mode information are automatically extracted from the exported s-parameter file. If group delay information is available as indicated by the header section of the s-parameter file, it is also included in the compact model. The group delay status indicates whether group delay is detected.

Element Name: Enter the desired element name in this field.

Icon: Choose an optional icon (.svg) for the element.

Library Mode: Pick the execution mode of the wizard, the selections are as follows:

Build INTERCONNECT Model: Generate compiled INTERCONNECT model in the /wizard/ folder of the script. You can import this model into INTERCONNECT by right clicking the “Custom” folder in the Element Library, and use “Redirect” to point to the location of the compiled models.
Add to Existing CML Database: Add extracted information into an existing CML database by selecting a master JSON file. When you select this option, an entry is added to the selected master JSON file, and model JSON files along with the icon (if specified) are added into the /source/ folder of the compact model library. You can then use CML Compiler to compile all models in that library.

Note: When you generate the compact model, numerous model parameters other than those extracted from the simulation file and those specified in the wizard are set to their default values. You can adjust the value of all model parameters prior to compilation by selecting “Add to Existing CML Database” and then modifying the model JSON file in the /source/ folder of the compact model library.

CML Compiler Path: Select the path to your cml-compiler executable file. After you select its path for the first time, the wizard uses the last entry for subsequent runs.

Once you have reviewed the collected data and edited necessary fields, press “Execute” to complete generation of the compact model.

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