# Application Example: TW Laser model gain curve fitting

The travelling wave laser model is now capable of doing gain curve fittings. The fitting is based on a text data file that contains the gain curves information versus carrier density and frequency; the generated gain filter coefficients data file can be loaded to the TWLM element to describe the gain.

This example shows the Traveling Wave Laser model's (TWLM) gain curve fitting function by using the script command mczfit. The gain curve data is retrieved from a text file with a certain format.

Find the example here: https://kb.lumerical.com/en/index.html?laser_gain-fitting.html